You dealt with the brother very lovingly - your kindness is beautiful. If I found myself in a similar situation with an elderly brother, I hope I would be as gentle, and encourage him to come and talk whenever he wanted to.
I would softly suggest that he works towards standing down/removed as an M.S., that way he won't have a bad conscience teaching falsehoods from the platform. Then going on F.S. just to use the Bible.
The poor man is going to need a helluva lot more support than most of us here needed, due to his fragile years.
He must be devastated - keep comforting him!
You could also inform him that there must be Bethelites, D.O.s & C.O.s all over the world feeling exactly the same as he does, but they are biding their time for personal reasons, so watch what he says in the cong.