Ex boyfriends son staying with me

I had a boyfriend that I actually told you guys about. He treated me well but was extremely abusive to his 19 year old. I will say his 19 year old was kind of disrespectful, but never to the point to deserve getting his head repeatedly smashed into a wall and being thrown outside. The last straw was him pulling a gun in his son because he found out he didn't turn in his homework (because my ex destroyed his laptop). I called the police and dumped him. I reached out to his son a while ago to check up on him. We talked and he did say he never had a problem with me personally. Just hates his dad. I reached out recently to check up. He looked and said nothing. I asked again and he said he's ready to kill himself. When I asked why he said him and his dad got into another fight and sent me pictures of bruises and a black eye. Then said his dad pulled a gun on him again and basically fucked his mouth with it which was the weirdest thing he's ever did. He had to repeat his senior year because stuff with his dad had him failing. But he was talking suicide and I basically said if he needed somewhere to stay I have a guest room. He declined. I insisted because I was scared for him. He said no until I convinced him to stay a few nights until he found somewhere else. He took all his stuff and in the car he said he needs to tell me something before he stays with me. I said what and he said "I have had this issue for a while... And I need things for it ... You know what nevermind". I said I can get him anything he needs and he said it's fine since he will only be here a few days. So he has been doing his school online and kind of staying quiet. He doesn't seem to sleep much. I'll be going to the bathroom and it's 3 in the morning and he will be chugging coffee saying stay awake stays awake. He hasn't found anywhere else to go so I told him if he needs me to get him anything for that issue I will and he just gets awkward and says he's fine. Apparently his dad tried to ask where he was but he hasn't responded. I've been trying to help him with school but he's so exhausted from trying not to sleep so his grades are taking affect. I just want him to feel safe and get a good night's sleep.