It's difficult, but you really need to move your parents to where you can get a good enough job to support and care for them. If your main concern is money, being willing to move anywhere is quite attractive to many employers (e.g. they need someone at the Dallas office, but the geeks all want to live in Austin).

Their desire to stay put does not override all other concerns. If you were rich, you could hire a full time nurse, but you aren't, and your whole family needs to accept that.

I saw this when my grandmother couldn't take care of herself anymore. My parents dragged her to their house kicking and screaming and moved her into my old room. There just wasn't enough money in the family for anything else.

Forgoing building a life of your own so they can stay in their comfort zone is asking too much of you.