Am I Obligated by Law to Continue Caring for My Mean Mother?

This sounds like a very difficult situation. While we cannot tell you about New York law in particular, you probably are not legally responsible for your mother. But would simply returning her to her home solve the problem? Social service agencies will likely get involved and look to you for assistance. It would probably make sense to consult with them now and with a local elder law attorney. It may be time to seek guardianship of your mother, to qualify her for Medicaid and either get her care at home or place her in an assisted living facility or nursing home. Even if she goes home for a while, it may come to this as her condition deteriorates. Find an attorney near you.