Gordy, so long he revalidates his ICAO CPL, he'd be better of getting part 61.75 foreign licence validation/verification. There's no point paying another checkride and written fee. Tons of information on PPRuNe about validation.
It's smooth if all well prepared. I've done it twice.
If going the FAA ratings route, he'd have to do IR checkride before ATP, not to forget.