My mother lived with us during her last three years alive. It worked out well for us as we had an apartment in our home that had a separate kitchen, living room, kitchen and her own bedroom.
We never had a need for outside assistance and having her so close meant the world to us. She did hit a nerve or two a few times as she wanted to be the MOM still, but it was all in love.
We were plenty fortunate that our home was big enough to accommodate her and yet we all had our own space.
My grand daughter was living with us also at that time and it was great to have so many generations under one roof. I miss it and her a lot!