Oh no!!!!
I am right there with you, Trippin.
I swear, we really are sisters of the soul or something. I have the same problem! We're never going to get rid of my MIL. She's with us
forever! And so my husband is relinquishing our office for her to have her own room, and moving into our bedroom, which is fine... but then puts me back out into the living room... (because our room is too small for everything.) Which then puts me back out into the same space as his uncle! Too many people, too few rooms!
I feel your misery! I agree if your mom is offering this person to stay, she needs to make space for her. And no, it's not self-centered to want some privacy and a place to feel safe and decompress.