Here my friend got trouble with his account was hack and he can't used post proof trough Blockchain bitcoin address wallet because always use with Binance segwit BTC address, Seems Binance not available for signed message Bitcoin,
In case if next time, tell your friend to stake his bitcoin address somewhere on this forum. Like on this thread:
https://bitcointalk.org/index.php?topic=5415038.msg61016580#msg61016580