and to directly attack altcoins purely out of spite
A bright side for you - I think the admitted 51% attack dooms his long-term participation. Stuff like that (either the 51% itself or the misuse of resources entrusted him) will probably be explicitly criminalized within the decade, and while if he's US or many places there can't be a retroactive law, having that crime in the past will make serious businesspeople reluctant to work with him.