First of all there is no need to talk as if Muslims have never had any suffering, had family/friends suffer from illnesses, had deaths, members of their family even rejecting Allah.
Allah created everyone, you would never have the inclining to imagine the person you loved unless Allah had already created them-you liked what God had created.
Everyone belongs to Allah! Not to you, even children are entrusted by Allah to parents. What atheists do is use up an excuse of not to be bothered about anything by saying Allah doesn't exist, its like saying I've made a mess in the garden-but just brush it off, as you want to continue to enjoy the life of this world.
Anyone who dies as an atheists go to Hell, they send themselves to Hell, it does not diminish God's Mercy as they send themselves there by their rejection, neither does it effect the Muslims, angels devotion to Allah.
On the Day Of Judgement all will be looking towards Allah, no one will care of each other, not a Mother for her child, as its about your personal relationship with God and not to anyone else (which of course people hold little value to). The person that you loved did not create you, God did, by saying that individual means more then all that God gave you including other people is completely wrong. We are very clear in Islam, a person that does not repent, goes to Hell, when they die they do not care, or think of you, only that they that should have accepted God as the angels have done.
Even people belittle everything their parents gave them to say they are going to toss it all away because of someone else, and they do such an enormity with God, when they say they don't accept him because of someone else- who did not give you life, who cannot help you, who does not give you food.
See you on the Day of Judgement with whatever path you choose.