Liz, this is just me---and many might disagree with me---but I would encourage him to seek help. His behavior is very worrysome and one has to live with their own morality as to reaching out to another human that is suffering. Personally, I would not l eave a person in his condition alone in a house. I think that he should speak with a doctor---and, perhaps he would be willing to admit himself for help. He could talk to his own doctor on the phone or go to an emergency room, also.
I speak for myself---alone. I worked in psychiatry for many years....so, I am especially opinionated on this.....
dandylion