Nomad. Just move on. She reacted badly. You learned that the kind offer opened a hornet's nest. You won't try that again.
You have all of the choices and power here, to define your limits, how far you will go.
I would think through how far you'll go with the condo, and where you'll stop. Then think of contingencies.
You can't stop her from undoing, wrecking anything good in her life. It may be time to involve her with her case worker and let her work out her life with the assistance of the "system" with only limited and tangential involvement by you and your husband. I may be at the brink of this myself, with my son. There are many disabled adults who don't have anybody more.
If our children only abuse and mistreat and/or take advantage of us and anybody else who tries to help, what in the world can we do? If they have no motivation to learn, that is a fact that is impossible to circumvent or avoid.