The comma shouldn't be there because "and a retired schoolteacher" is not equal in status grammatically to the part of the sentence preceding it. Worse, you simply don't use it in a short "both-and" construction. It's plain wrong.

"Both Cyril and Mary play the trumpet."

"Both Cyril, and Mary play the trumpet."

"Both Cyril, and Mary, play the trumpet."

Take yer pick. I know which one I prefer.