You mean he has a linked-in profile that claims he's from the USA.
I got a lot of emails from people claiming to be US soldiers who found a bunch of money in Iran or Iraq. All I had to do was pay some money up front, collect the cash, and send some back to the person who emailed me about it. For some reason, I'm so special than at least a dozen different soldiers made me the same basic offer with only small differences in the details. I think all the money there is cursed, since the soldiers who find it keep ending up in the hospital and needing my help to move it. I'll bet if I asked, they could have whipped up fake linked-in profiles to prove they were legit.
Think this through. On the 0.0000001% chance that this ethical hacker actually is a hacker and not an obvious recovery room scammer, what's he going to do?
1. Hack the company's cryptowallet and send what's owned to you.
2. Hack the company's bank access and send what's owed to you.
If he's so skilled, he could do this and just send you your share and send himself his share - no need to collect upfront money.
If somehow he's too inadequate to send money to himself, he'd still be committing crimes because you personally paid him to commit crimes. The people who investigate cyber crime don't care what your motive is. Hacking wallets and bank accounts is a serious crime. Your ethical hacker will tell them exactly who hired him in order to get a reduced sentence if he's caught, even if it's years later on a different hacking job.
Of course, he's never actually going to hack anything. He's going to collect that upfront fee. Then he'll need more money for item after item. it will always be the last thing before you get paid, except there will always be one more new last thing each time. He may even send you unspendable bitcoins and need more money to unlock those for you. There is only one thing you can be sure of. You'll just get to keep paying and paying until you have no cash left to pay.