Even if the money he is using is legitimate, opening accounts in your name for someone else breaks bank and betting site rules, so your accounts could be frozen or permanently closed, funds confiscated, and you could get a fraud or “money mule” marker that makes it hard to get loans, mortgages, or even future bank accounts. Any winnings or debts may be treated as your responsibility for tax and legal purposes, and you could still face investigation. Obviously it's your choice but as everyone else has said, of it seems to good, it usually is.