But if it has not he needs only a bit of instructor time, no other SEP flying. Is that correct?
Well if it hasn't lapsed,
legally he can get in and go (without passengers). Sensibly and practically though, it's the usual checkout stuff, but I always demo the first approach and landing having had airline pilots try and flare at 30' and another having been warned by colleagues to resist all feelings that 30' was just right, he tried 'minus 5'.
Presumably if his SEP rating is still valid this should not apply, the ones I was talking about hadn't flown SEP since the 60s!
If he builds 12 hours (inc 12 LATOs and at least 6 hours p1) he should be able to get an SEP sign off