If he tests negative then he is good to fly, there’s nothing to check
It only becomes an issue for vaccinated purposes, you have to wait a period after getting it to get the vaccine, before that you can get a doctors note saying you are recovered from Covid in lieu of being vaccinated
any documents I’ve seen about flying after being Covid positive have said that you had Covid within the last 90 days, wouldn’t make much sense if you had to wait 90 days to fly.
Think you just need a negative test and a doctors note
honestly they could pick someone with an IQ above room temperature to give it a “dry run” and alleviate 75% of the confusion and problems, the other 25% I don’t think the applicants are literate