. I agree with my T that she needs to go but my heart hates to see anyone homeless and me be the cause.
I'm going to put what's likely to be an unpopular alternative way of looking at your current situation...
Yes, you mother failed you miserably in protecting you from your cousin, and healing from that may require some degree of physical seperation to allow the emotions space to work through the healing process (which may or may not include forgiveness- that's entirely your call).
But booting mum out and making her homeless?
Telling you she needs to go is easy until I put myself in your position. Would I make my (otherwise reasonably good???) mother homeless because of that one heinously bad choice she made when I was a child?
Honestly I don't think I would. I don't think I could. My healing process is first and foremost about my relationship with myself, and watching my mum struggle with homelessness for failing to protect me when I was a child - in my situation she did a lot of other good things for me. Failed miserably in protecting me from my abuser, but sadly, so many millions of mothers all across the world are guilty of that. That's not an excuse, but it would place my decision about whether to boot her out in context.
Would I have a good, healing relationship with myself if I made my mother homeless for what was a heinous, but sadly very human, error on her part? No, I don't want to be that person.
What I would try and do is be more assertive with her that her living with me is not a permanent solution, and really activating the "You need to find new housing" button with her.
There is no onus on you to house your mother. There is no onus on you to ever even forgive her. But what is your relationship with yourself going to look like if you make her homeless? Idk, only you can answer that...