He needs credit and will need it soon...most likely.
You may have mentioned it but why will he need credit soon? Vehicle purchase or home purchase?
If it's a vehicle purchase he can obviously just save up and pay cash. If it's a home it gets a little tricky, but he can research manual underwriting and save up that 20%+ down payment and he'll find a lender that will play ball (assuming he can pass the manual underwriting). Or you can just co-sign.
I was in the same boat after I got out of the Navy - I had saved up enough for a down payment on my starter house but I had zero credit. Parents had to co-sign.
Any other option will take years.