My mom only has social security and lives with me. How can I get her into an assisted living on ss only?

She didn't qualify for Medicaid. I pay for all additional expenses. My sister won't help and although she lives only 10 minutes away, she hasn't called or visited in the past six months. My husband is going crazy with this situation and it is putting a toll on my marriage. My mom doesn't have any property, no savings, nothing. I am stuck. Any suggestions?