Have you ever tried taking him out? It's somewhat possible he may like it which may seem out of the norm because it's out of his daily pattern.
A suggestion from a nurse in that specific area has said maybe to slowly make it part of a pattern that he can get used to. Make it safer for him by introducing him to one thing/event at a time. Time consuming possibly but with perseverance and patience it may work out just fine.
So I'm not speaking from personal experience but I do happen to have somebody close to me who has been in that area for the last 14 years, perhaps that advice can assist