The person involved has no neemonus.
WHO says he needs ne’emanus? The default assumption is that the conversion was valid.
Gerus is not for amateurs
Neither is passeling a geirus b’dieved for amateurs.
Believe me, I don’t think the guy’s a tzaddik, but unless there’s a psak from a legitimate posek passeling his geirus, I think we have to assume it was valid, and unfortunately, this Yid is oiver on huge aveiros (M”Z and chillul Hashem).