How about this:
We put up an “Unban Daddy Wankaloo” poll on Monday morning with simple yea/nay options. If by noon on Friday, the yeas have 2/3rds of the vote, he’s unbanned. If the yeas don’t have the votes, he remains banned and we never raise the subject again.
Also consider that even if unbanned, he says he won’t come back. Chances are unbanning him will really mean nothing.