So the new accusation is: "I don't trust them because they lost access to an empty wallet and pgp key"?
I'd expect someone like you to know better than that. Statements like these are part of the reason for which we have failed to prevent a number of scams. One of the most recent cases is
nachius.
I can't help with that, but as MZ offered a proof of knowledge. Would that be acceptable? I can think of a question only they should be able to answer based on our past exchange of encrypted messages.
That is proof-of-proxy, i.e. you. Whether you can be trusted with that is debatable for each individual. I'd prefer cryptography over trust. Anyhow, the password problem with Windows can be semi-easily mitigated and thus voids the excuse.