Hi ThisWayOut...
Is he going to be staying at your mom's place? Is there anyway for you to get away for a couple days (maybe stay with a friend)? Or can you plan some activities that will at least get you out of the house as much as possible? Like... spending time at the park, the library, maybe finding someplace to volunteer? Anything so that you put some physical distance between you and him?
If not, could you feign illness and lock yourself in your room for the duration? I think getting away would be a bit better (for me, I think I'd feel worse being stuck in the house with him). But if not, locking yourself in your room because you're "under the weather", "fighting off a cold", or "may have been recently exposed to some weird flesh-eating bacteria, and would hate to accidentally spread it to anyone else".... could at least help you minimize interactions?
And, I'm so sorry ThisWayOut. That's really awful timing with the new memories and you waiting for a new T. You shouldn't have to go through this, especially alone, and I wish there was more we could do to help.