Yep, he's got an Faa (USA) ppl, you can either do the course there or do a UK ppl first. It's really straightforward then to get an Faa ppl based "piggy-backed" on that.
Main reasons folks do it is that US has a much more reasonable approach to maintenance for light aircraft plus a sensible training/exam approach to the instrument rating.
If the Secretary of state sees the sense in registering his aircraft in the US and having a US ppl you'd think he of all people would be in a position to try and start to address the UK issues.
But apparently not.