I would look at both independent and assisted living alternatives depending on what level supports his needs.
Independent living arrangements can vary quite a bit, but in general it should involve having his own apartment in a seniors only community that serves 2-3 meals per day in a dining room and also offers basic support, such as transportation to stores or the doctor. Depending on how nice it is, these can run anywhere from $2000 per month and up. Independent living is usually defined as “can he get from his room to the dining area on his own.” If he can do that and take care of his own hygiene then independent living is the way to go.
Assisted living brings in additional medical support and care, primarily distributing medicines as required under a doctor’s orders as well as housekeeping, laundry, and limited personal care. My grandmother is in assisted living and pays about $4000 per month for her room and other services.
He may want to talk to an estate and / or tax lawyer to arrange his finances before going into these. He will have to pay these out of pocket (some of which is tax deductible). Unless he is destitute (and this will vary state-to-state) it is unlikely there is much financial support available for him. Destitute is defined by the government, not reality, so it is good to get a lawyer involved as they can set him up to look destitute in government eyes.
On plus side, senior communities usually plan several events a week so there is always something to do. Also, as a male, he is likely to find himself in a target rich environment. Judging by where my grandmother is, there are about 80 little old ladies and about 10 older gentlemen. From what I can gather from the staff and some of the more talkative residents, several stay fairly active with the opposite sex.