They won't pay you $45k because they won't say they're responsible. It's true they could've stopped you because they knew your ip address. If you'd won they wouldn't pay because you had many accounts so they're responsible but won't help you.
It's a sad story. You've created accounts to gamble & lost $45k which didn't belong to you. Why did you keep $45k money which belonged to other ppl ?
yes it's a sad story and he can't do anything about it, I don't think the platform will give him his money back, the fact that he bet that money that didn't belong to him is already very serious and would be enough to make it clear that the mistake is his, I fear he will never see the money again