he was the only astronaut to have made 4 space-flights
Hate to quibble given the context but for accuracies sake surely Jim Lovell beat Young to that honour by about two years or so..?
( in Lovell's case, Geminis 7 and 12, Apollo 8 and made it to four flights with the infamous 13 in Spring 1970... Young got to four flights with Apollo 16 in spring 72)