-snip-
Being able to sign a message from an eth address that has been posted on this forum should suffice, there's no point in writing the binance's bitcoin address.
Btw, if signing an ether address is considered valid on this forum then your friend is in luck, I hardly found anyone ever using this method for account recovery.
I'm also not sure whether sign messages other than BTC address and PGP key for Bitcointalk account recovery will be accepted or not.
Often, you need to prove ownership of the account with a PGP or Bitcoin signature. -snip-
However, I've read the following global moderator statement:
Please tell me which method you prefer, I think I have enough proofs and is obvious that is my account.
A signed message from a bitcoin address is likely the only thing that is going to get your account back. If you can't provide that then you should at least try sort the ethereum one out.
Maybe the OP (his friend) can try it if he has never posted a bitcoin address from a non-custodial wallet.
@OP, I've tried to create an eth address sign message:
https://bitcointalk.org/index.php?topic=3383051.msg35709111#msg35709111. You can see the full tutorial in
the first post by @setaw on that thread.