What to do when his family doesn't care?

I have been his landlady for about ten months. At first, he was the perfect tenant. Early in May, we took him to the hospital. His blood pressure was elevated, his blood sugar was through the roof and he could not make a coherent sentence. I was told he had a stroke even though I saw no physical symptoms. After he was discharged, his mental confusion gradually diminished. Now it is back and he has developed physical symptoms. Incontinence, loss of balance, confusion, inability to swallow. His family has turned their back on him. I honestly don't know what to do with him. I now he is a diabetic and has high blood pressure. And he abuses pain medication.