Sorry for this being long! ( I wrote this last night, but it was really late )

Backstory: Me and my fiancé have been dating for 4 years (both 21) and finally moving into an apartment of our own! As long as we’ve been together, his mother has a boyfriend (lets call him Billy) and Billy is not allowed to work at all. Her reason being that she needs someone to her son that’s on the spectrum. Her son was fairly young when we started dating, but now he’s in school and Billy still isn’t allowed to work at all. Even when they had an aide to assist her son, Billy still had to stay home to watch the aide. Basically, Billy isn’t allowed to work or go outside (unless he’s going to family)

What’s going on now: Me and my fiancé live in NY, but we’re moving out of state to N.C. I just recently learned that his mother hated the idea of him moving in with me here in NY and when he gave an idea of him possibly moving out of state, she was completely against it. (In her defense, we’re moving after two months of talking about it. But with the amount we get from unemployment, something that would have taken us months to do, only took us a few weeks. We have enough for the apartment, furniture, and a car. I have a secured job and he has interviews lined up). We’re moving the second week of August and after years of Billy being prohibited from working, his mother is now allowing Billy to work and is asking my fiancé to be the permanent care person for her son. My fiancé told me that he isn’t going to do it and we both find it eerily suspicious how she is against us moving and a week before leaving, she’s asking him to stay in NY to do this for her. His plan is to tell her he moved AFTER we’re there because of this behavior she is exhibiting in trying to force him to stay. (Mind you, Billy isn’t really allowed to do anything and she’s asking my fiancé to take this role.)

I tried venting to my parents, but they’re kind of old school and are all like “family is family” and “if something happens to him, who is going to run to his side and help him.” They were kind of negatively speaking on the situation and making it seem like the situation was trivial and that we’re making it bigger than what it is. I spoke to my siblings and they agree with me that she is doing this in order to have some type of control over my fiancé.

Am I being crazy? Should my fiancé be worried?