Don't go home again ever while mommy haas this jerk and his asshole kid.
I would move heaven and earth to accomplish this. If I wanted to see her, find some restaurant and meet her there: if she drags whacko along, I would turn and walk out.
I can understand though on timing things so, if I have to get out, I do it on my own terms (I did that with my own whacko moo at one point.) My mom calmed down in later life, but the problems she has work out in other ways. If I were more successful, my mom would be totally on her own most likely, forcing her to reach out to others. At the moment, it is mutually beneficial for me to be downstairs.
Best of luck to you.
(I am always reading how these whack jobs finally go totally off the deep end when they get off meds.. don't be a statistic or let your critters become a stat as well.)
ps: as an example, there was some farking schizophrenic that seemed to have pulled it together, was living a somewhat normal life, even had a shack up honey who was stupid enuf to get knocked up with the defectives bastard baby. This was a 'poster child' for the 'see how normal schizys are?' organization. Well, the inevitable happened, he whacked out despite the meds and killed the gf, the in-utero bastard and himself.