He has no income, can't demonstrate a specific skill needed in America. He's not even qualified to be on a landscaping crew.
As such he is likely to become a public charge and a drain on the US taxpayers. Additionally he entered the country claiming to be a non-immigrant and now wants to become a permeate resident. Thus his initial visa application was gained through fraud.
Deportation is in order.
Any person can enter the US on one status and decide to change the status later. It is extremely common for someone to enter on a non-immigrant visa and later decide to stay. As long as this decision isn’t made too quickly (such that it suggests the initial entry was not in good faith), there is no issue. Besides, he is married to a US citizen which entitles him to adjustment of status to permanent resident in almost any situation. It would also have been a trivial process for him to apply for an immigrant visa at a US embassy in the UK (but he would have had to wait for processing before arriving in the US). Once he arrived on a nonimmigrant visa though, he could overstay his visa for 5 years and all would likely be forgiven with a green card application as a spouse of a US citizen, as long as he wasn’t stupid enough to try to leave and come back before the deal was done. There is lots of leeway given in the law for USC spouses. Disclaimer: I am not a lawyer but I know a lot about this process, including personal exposure.
He could do Hallmark movies. Lots of European princes in those plotlines.