My brother was diagnosed with dementia but passes the cognitive test. How do I care for him?

My brother has no immediate family and moved in with my husband and I. He won't bathe, brush his teeth or clean his dentures. He cannot cook for himself or use the microwave. His PCP is no help. He was diagnosed with on set dementia but no medication was prescribed?? He won't eat unless we place the food in front of him. He has no money or pension. I have tried to get Medicaid and can't. He needs to be watched 24/7 but sometimes that is impossible. After a surgery I placed him in a facility to recover (I am not the nurse type). He was cathetered and bleeding. Medicare denied to pay. He craps in his pants and won't shower daily or every other day. I feel I am a prisoner in my own home. I am at a loss as what to do next.