how to say hell no... you dont lol as much as I would want to say that to my visitors I dont. heres something that worked for me with a relative ....

we were sitting down talking and I knew they were gearing up for the move to my location and being the only relative in the city I was the logical place to stay with. My wife and I had already discussed this kind of situation of having our respective relatives move in for a bit and we decided we did not want to be in that situation with an odd relative that may come and never go.

I brought up the move in a non threatening way...

I hear you want to move here to the city. have you decided what kind of place you are looking for and what price range you are looking for? I have some time off coming, I would be glad to go with you to look at some places.

relative... ummm yea I havent thought that far ahead, I was wondering if I could stay with you and sandy for a bit.

me... Im sorry thats not an option because of our jobs and kids and well you know how it is with living with relatives, the best way to ruin a friendship is to have friends and relatives move in with you. I really like our relationship right now and I dont want that to go south because I would be your landlord. We have bills here and another person means higher bills, which means the one moving in would have to pay their way.I really dont like the idea of that. But I will help you find a great place all your own near by where we can be a part of each others lives as much as you would like to be, heck you will think you live here but will be able to get away from the chaos of this place by going to your home its not easy living with very young children one being a special needs one. How about tomorrow we take the city transport around the city so you can get to know the neighborhoods and we can go from there.

The next day while touring the city we passed by many for sale and for rent signs, some we stopped at and checked out the places. with in a week my relative had signed the lease for their own place not too far from my own.

suggestion instead of telling your mother hell no, sit down and figure out exactly what kinds of hardships it would be to have her live with you (not including the DID stuff, remember relatives cant see inside your brain and mind to see what chaos their possible moving in will do to you, but they will be able to understand bills, small space, lack of extra bedroom, lease agreements with the place and HUD/Section 8 or other housing assistance... tangible things like that. if she is on government assistance that would also possibly get affected...)