Psychiatric hospital advice

My son, (M21) is going through a horrible time. His abusive girlfriend and him are battling again, his dad, who he lives with, is expecting a new baby any day, and will be moving to Arizona next month with his new family. The plan was to have him move back into our family home with me and his sisters, but after this last episode both me and my ex don’t believe that will be a safe situation for anyone. He’s too destructive to live on his own, his personality swings make it hard for him to hold down a job, he’s facing multiple legal consequences of his actions,and he is also a hoarder level collector of trash. Does anybody know anything about being admitted to a psychiatric hospital, does BPD qualify, he’s had idealizations of stoning me and gouging his fathers eyeballs out with his thumbs. I’m just hoping he could get as much intensive therapy as he could get at a time so we could get him in a place where we could at least communicate with him about his options and that we could feel relatively confident either with him living back with me or finding him his own place. I’m truly terrified if left on his own, he will disappear and I will never find him again and he’ll suffer alone.  Has anyone had any experience with this? Was it helpful at all?