The only waivers I've ever seen people actually struggle with getting are medical waivers. I entered the nuclear program on an academic waiver, same situation really. I have several friends into their late 20s who joined, so I can't really see that being an incredibly difficult waiver to get. Your son got the max score on the asvab, so his recruiters should definitely be pushing to get him in. I look forward to seeing your son out in the fleet.