ECF can poison him as a way around the 2 lynch requirement. Or maybe we have a vig who can kill him. If these powers are handed out randomly having to lynch someone twice might be too risky to keep around on the chance they are mafia. My theory on these powers is the leaders are townies who get to hand out powers or else it's random.
I would suspect we gain no info from lynching him based on the wiki it sounds like the day would just end.
http://wiki.mafiascum.net/index.php?title=Lynchproof