marriage question?

[khadijah7]

Assalamu Alaikum Warahmatullahi Wabarakatuh I am a convert and am still learning the ethics of what is permissible and what is not in Islam. my question is, i am married and we live away from both families. Is it allowed for my husband to be left alone with us unmarried sister? As, i do know if they live together and both are not married it is okay to be left alone. But, in my case we are married and she is of age to be left alone, but his mother tells him to stay at home with her so she won’t be alone? It doesn’t make any sense to me, please if someone can help me understand this i would greatly appreciate. shukran.

[SishFish]

Salams, could you please clarify: who's sister is he being left alone with?

[khadijah7]

Assalamu Alaikum Warahmatullahi Wabarakatuh, his being left alone with his 19yr old sister. My question is even though his married and doesn’t live at home, it is okay that his mother tells him he has to stay at her house with his 19yr old sister alone when the mother goes to visit a family member?