Okay, I see that he'll be an airdale, Pensacola is nice, I was just there last month. I would check out Arizona's benefits on college before electing for the GI Bill. I chose the GI bill but in my state, we have the Hazelwood act which gives you 150 credit hours tuition at a state school, BUT you have to use up your GI bill first. Career guys have little use for the GI Bill, had I elected a bonus, I could've invested it and been happier than with the GI Bill. If he plans on only doing his first enlistment and getting out, the gi bill can help.
One thing I would've done differently: Set up a Roth IRA before shipping out, and setting up an allotment to max it out every year. Retiring after 20 years on an enlisted salary is only possible if you have a good amount of money saved, another job, or you retire to a 3rd world country.
Also, prepare yourself for a lengthy deployments. He has a good chance of ending up on a carrier and they do the longest deployments in the Navy.
I love being a Nihilist, there's nothing to it!