If you found that out through PADI and NAUI, then I find it believable. Even if his status is "revoked" by either PADI or NAUI, I find it hard to believe that they would reveal it to you.
Some folks choose to not "renew" their instructor status, that does not mean that it is "revoked".
Some folks choose not to carry liability insurance, and let their certification lapse.
If you can prove that it is truly revoked, then that is a different story. It is still extremely hard if not impossible to imagine that 2 certifying agency would revoke both his NAUI and his PADI certification. The process is so complex, it would be hard to believe that even one organisation would revoke his instructor status, that having 2 revoking his status - would be almost unbelievable.
Check your sources before you spread rumor. Rumors are very harmful, and also unlawful.