My mother has advancing dementia. Not sure if your mother is capable of this at the stage she is in, but the best thing I ever did was get my Mom involved in an adult day program. She has been in two now (we moved), both operated by Continuing Care Communities with religious affiliation. But there are lots of various programs to chose from in our area. Several are run by a non-profit but use church facilities.
She chats away with others in similar circumstances. They do chair exercises, sing hymns, play Bingo, arts & crafts.... Some participate more than others.
It keeps her awake most of the day. (They "rest" after lunch.) Keeps her mind as active as possible and keeps her around other people. She never can remember what went on, only that she had a good time.
Prior to living with me, she had been living with my sister and dozing off in a chair most of the day. She didn't know whether it was night or day most of the time. She had lost so much muscle tone that she could barely walk and it was a struggle to get out of a chair.
I realize that one day she will not be able to participate even at this level and will likely spend most of her time sleeping. When that happens, she will no longer attend the day program.
But until then, it has been a lifesaver for her and me. There is no way I could keep her entertained and engaged the way they do for hours on end.
Plus, given her N tendencies, she loves the attention and the fussing over her. One of her favorite conversational gambits is, "Guess how old I am?"