He flew a solo triangle round robin route with a total nonstop flight time of 7.4 hours
Where I learned to fly we were specifically forbidden (through the flying order book) to plan non-stop/unrefueled flights longer than 2.5 hours. For the PA28 and C172 exceptions were occasionally made (after a careful check of the plog/fuel plan), but not for the C152.
I'm very surprised that the C152 can have an endurance of 7.4 hours (I presume long-range tanks?) but even more so that an instructor would sign a student out to actually do these kinds of flights. At night even.