Re: Extradite him?
He's not one of ours so the alternative would be to send him back home to Portugal as an undesirable alien. Portugal can then send him to the US.
The Beeb report says another 21-year old co founder was arrested in the UK with "£5,000 in cash, thousands of US dollars and ... crypto assets worth more than half a million dollars." Presumably US dollars don't count as cash.