First off, he does not need an aviation degree to become a pilot in the military. I know military pilots with English, economics, and biology degrees. An aviation degree wouldn't hurt him, unless he needed something to fall back on, but it is definitely not necessary.
ERAU has a good ROTC program. I believe it's the largest detachment in the country and they get a lot of pilot slots. However, there is a lot more competition for pilot slots, so it may be all relative.
The fastest way to be a pilot in the military is NOT to enlist. It is to become an officer, whether it be through the Academy, ROTC, OTS or AMS and to proceed to Undergraduate Pilot Training. That is the fastest way to the cockpit of a military aircraft. Take what a recruiter tells you with a grain of salt. They have one job and that's to meet quotas. Most of them know NOTHING about being a pilot in the military. If your son wants to know what being a pilot in the AF or Navy is like, he needs to ask a pilot in the AF or Navy.
The good thing about the Air National Guard and Reserves is that your son can get a job as a computer programmer (big bucks) and still be able to fly military aircraft part time. On the other hand, the option to retire after 20 years of service in your early 40's with 50% of your base pay and full medical benefits is not there in the Guard or Reserves. Retirement in the guard and reserves is based off of points and you have to wait until you're 59 1/2 to collect your pension.
Make sure your son chooses wisely. Pilot slots are competitive and there are no garauntees he will get one. It's a lengthy process that starts with the commisioning source. With ROTC, when and if he does get a slot, he has to pass a flight physical. If he doesn't pass and can't get a waiver for what DQ'd him, he owes the AF 4 years of his life doing.... who knows?? Needs of the Air Force. If they think his qualifications fit their needs in Space and Missiles, he will be going to Space and Missiles. Oddly enough, Space and Missiles personnel wear flight suits, but they're 200 feet below the surface of the earth. If he passes everything with flying colors and makes it to pilot training, he's got at least a year of training before he makes it to the cockpit of a weapons system. For example, to fly KC-135's, it's going to take roughly a year to complete Phase I, II and III of pilot training, 3 weeks of Combat Survival School, a week of Water Survival School and then 3 1/2 months of KC-135 training. For me, this took about almost 20 months before I was out of training and into an operational unit.
I recommend he stay in his degree program and either apply to OTS (active duty AF), OCS (active duty Navy) or go for the ANG, AF Reserves, or Navy reserves after he gets his degree.