My brother has been at my house for 2 weeks and still won't tell me what's going on

I hadn't seen my brother in the last 8 years and he came by my house two weeks ago. It's a complicated messy story but my former step mother started sexually abusing my brother when he was 11. Nobody found out about it until he was 12 and my mom reported it and she did do a very short amount of time and my dad had decided to get back with her. My dad always says his decision to do that was complicated. My brother technically wasn't supposed to be over there with her anymore but I guess she "went to therapy" and was ready to be a normal step mother. We didn't know until he was 18 that it started to continue and my brother basically started to like it and long story short he ran off with my former step mother at 18 and they got married. It destroyed my family. My dad hates my brother for ruining his marriage and my mom doesn't really talk about him. Well he showed up at my home after 8 years. I hugged him because I didn't know if he was still alive. I asked where he's been and he told me he had been living in a few different states. I asked about... His wife and he said he would like to not talk about it right now. So he's been here two weeks. How long before I ask again? I don't want him to leave and it would be nice to have a Christmas with my brother again but I do want to know what's going on. None of my family knows he's here and he said he would rather keep it that way for a while. I guess our dad had messaged him after he left home and said he was dead to him. I like having my brother back but I am concerned on what's going on