Can't afford help, what to do next?

Everyday I read these discussions and almost always wonder where do we get the strength to cope with the endless problems of caring for our elderly loved ones. It affects every aspect of our life!
I've been helping my parents manage their finances, health, and everyday life in general much like you all do but they do not live with us. My father died about 6 years ago and I have to say he was so easy to care for in that he never complained or demanded much and our conversations were simple and pleasurable most of the time. On the other hand my mother, who has a huge personality and is a 40 year old stuck in a 84 year old body is just the opposite. She can be a lot of fun when she feels good but at her age it's only in the afternoon that she feels good. She can be demanding and there's always a crises in her life or she's dying from something or having a heart attack (which she's never had). Everyone loves her when they meet her but they're not her daughter. I know she's getting to the point where she will no longer be able to live alone and I have no room since my husband and I live in a small condo and my mother does not have enough money to go into assisted living. She makes just enough money not to qualify for any gov't financial assistance. My brother won't take her in or help in any way, what do we do next? I work and run all mom's errands, take her to her doctor appointments, wash her clothes, shop for her groceries. What more can I do, and I know she'll need more soon. What do other people do when you don't qualify for anything. We live in the San Francisco Bay area and it's very expensive to live here. Any suggestions?!