Let’s think theoretically, not practically.
A laymen has accused a Bishop of sacrilege. What’s the worst they can do to him? Excommunicate him I suppose.
But think about this. A layman is laying the most serious charge possible on a Bishop of the Church. You seem to agree with him.
What are you going to do about it?
Help me out here --- I need a clarificaton. When you say "excommunicate him," do you mean excommunicate the Bishop, or excommunicate the layman?