This is quite ironic since here things are the opposite! The mother is treating the child badly coz of his difference in faith. Anyways, mothers are to be treated kindly no matter what their faith.
Taken from:
http://www.al-sunnah.com/convert/a_m..._of_mother.htm
My wife's mother has in effect cut herself off from her daughter in recent times. Whilst there was some form of communication it was often quite turbulent and heated. My wife has tried a number of times to re-establish contact yet her mother refuses, quite stubbornly, to reply. We are both reverts and have often felt that our acceptance of the religion has played some part in her mother's negative attitude. I would be grateful if you could advise us on what me might possibly do to rectify this situation.
Jazak Allahu Khairan
Praise be to Allah,
The reactions of non-muslim mothers towards their children's embracement of Islam varies. Some mothers are peaceful and passive considering this as a personal matter which does not affect the relationship between the mother and her son or daughter. In such cases more piety by the child towards his or her mother will make the mother admire and respect Islam.
Other mothers adopts a more stubborn approach at the beginning but the mother finally gives in and accepts the new religion as a fact of life after she sees the child's determination and persistence which could lead the mother herself to embrace Islam.
In the third case we find that some mothers are constantly stubborn to the extent that she might hurt and oppress her son or daughter. Usually such mothers are blindly prejudice because they consider that her son or daughter had gone astray by leaving the faith of his fathers and ancestors and she must do something to help go back to the right path (according to the mother).
The following are three stories that took place at the time of the Prophet , Peace and Blessings be Upon Him, that involved three of the Sahaba (Companions of the Prophet , Peace and Blessings be Upon Him) which illustrates the reactions of their mothers after they embraced Islam:
Story #1
On the authority of Asmaa' Bint Abi Bakr she said "My mother came to visit me one day. At that time she was still a polytheist and there was a pledge between the Prophet , Peace and Blessings be Upon Him, and Quraish (one of the great tribes in Arabia that lived in Mecca in the pre Islamic Period of Ignorance who used to enjoy great spiritual and financial powers). I requested the Prophet's , Peace and Blessings be Upon Him, religious verdict and said: Oh Prophet of Allah, my mother came to visit me, seeking my help; should I keep a good relationship with her? Yes, keep a good relation with her said the Prophet , Peace and Blessings be Upon Him:. Reported by Bukhari and Muslim, and this narration is listed in Sahih Muslim under # 1003.
In another version narrated by Ahmad, on the authority of Asmaa' Bint Abi Bakr she said " My mother came to visit me when she was still a polytheist and she was living amongst Quraish. She was desirous, meaning in need, so I asked the Prophet , Peace and Blessings be Upon Him, and said: Oh Prophet of Allah my mother came to me and she is a polytheist and she needs help. Should I keep a good relationship with her? He said yes maintain a good relationship with her.
Story #2
On the authority of Abu-Huraira, who said: I used to call my mother to Islam when she was still a polytheist. One day, while I was calling her she mentioned something about the Prophet , Peace and Blessings be Upon Him, that I detested. So I went to see the Prophet , Peace and Blessings be Upon Him, while crying and told him: I used to call my mother to Islam and she would refuse. I called her today and she mentioned something about you that I detested. Please invoke the blessings and guidance of Allah on her. Then the Prophet , Peace and Blessings be Upon Him, said: O Great Allah guide the mother of Abu-Huraira. So I left full of hope because of the Prophet's supplication for my mother. When I reached home I found that the door was partially closed. My mother heard my footsteps and said: Stay still Abu-Huraira, then I heard the water running; he added my mother performed body ablution, put on her cloths and hurriedly opened the door without her head-cover and said: "None has the right to be worshipped but Allah and Muhammad, Peace and Blessings be Upon Him, is the Messenger of Allah". I went back to the Prophet , Peace and Blessings be Upon Him, crying of joy and told him: I am bringing you good news; Allah answered your prayers and guided the mother of Abu-Huraira. The Prophet , Peace and Blessings be Upon Him, praised and glorified Allah and said: this is good. I said: Oh Messenger of Allah, pray to Allah to make me and my mother beloved by Allah's believing slaves and make us love them. The Prophet , Peace and Blessings be Upon Him, said: Oh Allah, make this little slave of Yours and his mother (meaning Abu-Huraira and his mother) become beloved by your believing slaves and make the believers love them. Ever since, there was not a believer who heard of me, even without seeing me, that did not love me. Reported by Muslim in Sahih Muslim (Muslim Authentic volumes) under # 2491.
Story # 3
On the authority of Saa'd (Ibn Abi Waqas May Allah be pleased with him) who said that verses of the Qur'an revealed his story. He said Um Saa'd (his mother) swore not to talk to him ever nor eat or drink until he renounces Islam. She said: You claim that Allah commanded you to obey your parents. I am your mother and I order you to do this ( to renounce Islam). He said: She stayed with nothing to eat or drink for three days until she fainted because of strain. Then one of her other sons named Umarah gave her water to drink. And she started to imprecate against Saa'd, then Allah revealed this verse in the Qur'an, which translates to the meaning of {And We have enjoined on man to be good and dutiful to his parents; but if they strive to make you join with Me (in worship) anything (as a partner) of which you have no knowledge, then obey them not. Unto Me is your return and I shall tell you what you used to do} Verse 29:8 - Surah 29, Al Ankabut. This Hadith is narrated by Imam Ahmad in his Musnad and in Sahih Muslim in his Sahih under # 1748.
Also, Allah revealed another verse in the Qur'an, which translates to:
"But if they (both) strive with you to make you join in worship with Me others that if which you have no knowledge, then obey them not; but behave with them in the world kindly, and follow the path of him who turns to me in repentance and in obedience. Then to Me will be your return, and I shall tell you what you used to do"( 31:15 - Surah Luqman).
Based on the above stories one can determine how to deal with a non believing mother and can draw the following significant conclusions:
The importance of good presentation of Islam to the non believing mother and to try to kindly persuade her and to strive to convince her as Abu Huraira did (story # 1)
Continue to do good to the non believing mother and to remember that her disbelief does not justify disobedience by the son or daughter and that doing her good does not contradict with your innocence of her as a non believer, on the contrary as it is stated in Verse 31:15 above, Allah has commanded us to treat the non believing parents kindly even if they strive to make their child a polytheist because of their rights as parents hoping that they will embrace Islam.
Continue to sincerely pray and supplicate for the non believing mother hoping that Allah may guide her, as evident in Abu Huraira's story (story #2).
The divine guidance of Allah may come after continuous strive by the child and strong objection of the mother as in Abu Huraira's story, therefore the son should never surrender or give up but should continue to pray and supplicate for the non believing mother.
Regardless of how hard does the non believing mother strive to make the son renounces Islam, and the pressure she will exercise against her son such as refusing to eat or invoking upon him , the son should never surrender or give in nor should he retrocede away from the righteous path as one of the Sahaba said to his non believing mother in a similar situation: :If you had one hundred (100) souls and it all left your body one after the other I will never give up my religion (Islam)".
It seems that the mother in question deliberately oppresses her daughter through estrangement which makes her emotional torn but that should never weaken the muslim or shake his faith and belief in his religion. There is no objection to make the non believing mother understand that you are not going to retrocede , however she (the mother) can kindly ask for anything and she will be immediately answered to it except for giving up this religion.
We ask Allah to quickly guide her to the righteous path and give you patience to call her to Islam and lead you to the righteous and correct way