Who's the Crazy One?

Let's see here: Mom has Lewy Body Dementia and lives on the secure floor of an assisted living facility, along with Alzheimer's patients and others with vascular dementia or similar types of impairment.
This is not a fun place to live, not a good stage of life to be in--almost 89 years old, approaching death--but I try to make her happy.
I think that my daily visits and the excursions on which I take her should make her content with her situation, along with the medications. She takes Zoloft for depression and Seroquel, an anti-anxiety med.
She's depressed and irritable, but I keep trying to fix everything for her.
I think, "If I do x, y, and z, she will be content and enjoy her remaining days."
Duh-- it's impossible. She's not going to be happy with her limited, repetitive daily cycle.
She's the sane one, depressed about it all. She's going to be unhappy and tell me about it.
I'm in denial, losing my sanity over trying to interact with her, take her out, cheer her up.
I need to accept reality and stop trying.
For my own sanity, I need to stay away from her or at least limit my time with her to one hour per day. These 5-6 hour excursions are killers. She says things that hook me into feeling bad for her, trying harder to spend time with her and take care of her.
But no matter what I do, she is still going to be gloomy about going back to Ocean View Assisted Living and being just another of the thirty crazy old people on her floor.
What she would really like is for me to take her into my home and spend 24 hours per day taking care of her: meals, bathroom trips, bathing, conversation, excursions, medical visits.
I can't do that, and even the amount of time I'm giving her right now is debilitating to my emotional state and my energy to carry out the other work of my life.
I don't know how people do it who are caring for an LBD parent or spouse in their own home, with or without help.
I do know that all of them sooner or later give up and place their family member in a care facility.

Comments on this subject by Melody Beattie in The Language of Letting Go (The Hazelden Foundation, 1990):
We can learn not to get hooked into unhealthy, self-defeating behaviors in relationships--behaviors such as caretaking, controlling, discounting ourselves, and believing lies.
We can learn to watch for and identify hooks, and choose not to allow ourselves to be hooked.
Often, people do things consciously or without thinking that pull us into a series of our self-defeating behaviors we call codependency. More often than not, these hooks can be almost deliberate, and the results predictable.