OK, now I get what you were saying.
No, a layman cannot be excommunicated for saying his bishop is guilty of sacrilege. No ecclesiastical penalty can be brought against him whatsoever if
- what he's saying is truthful, and
- he does not urge insubordination against the office, or contempt against the person of the bishop, e.g. physical attack, verbal abuse, apostasy, schism.
There's a Canon on that, but right now I don't have time to look it up. It's basically, you can't say "My bishop is a --- I'll put it in Latin ---
saquus shitentiae," or words to that effect. :o0
Canon Law cannot be used to penalize anyone who is respectfully exhorting his ecclesiastical superior to act lawfully.
People who did that are canonized saints, e.g. St. Catherine of Siena.
Can you think of a more serious charge than that a priest is committing sacrilege with the Blood of Jesus?