Hello BPers

I am in a scenario where I hope the BP community will come through with some advice. My brother is physically disabled with MS and rheumatoid arthritis. He has been on disability for several years now and lives in a home that was purchased by my sister's boyfriend. My brother pays him $700/month which would normally just cover the mortgage but the owner of the house paid cash and never took a mortgage. He now would like to sell the house to buy a flip house. He offered to sell me the house basically at break-even for him. My PITI would be $800.

My brother has been turned down for Medicaid and food stamps because he makes "too much" with his disability check($2100/month). After he pays for his health insurance, medicine, food, and utilities he barely can afford the $700 rent. If I were to buy this house what are the odds of me getting him section 8 vouchers and using them to help me pay the mortgage and allow him to have some spending money? 

Any insights or advice would be great.