This describes the exact situation my grandmother is in, and what I do for her. I love my grandma, and don't give the actions a second thought. I like helping her out. However, it's apparent she's slipped into depression because of her lack of mobility/sociability. She's ready to die, and I can only hope that it comes soon for her.
I love spending time with her, but I hate to see her in such emotional pain (let alone physical). She always puts on the best 'happy' performance she can when family is around, but I know she's hurting.
This is the type of old I fear becoming.
It's great all that you do for your mother!