Just my 2 cents but the path he is thinking of has multiple flaws.
1. As stated if he goes AFROTC he will go ADAF upon commissioning unless they get permission from HQ AFROTC to go Guard, which would be hard since he will have his career field, i.e. pilot slot by the time he is a junior and the AF is short on pilots. IOW why would the AF allow them to go Guard over ADAF when they need them?
2. He must apply to the Guard unit. The problem is there will be people like my DS (ADAF pilot) that will do 11 yrs and go commercial, but because in the early years they get paid very little they do Guard. It now comes down to why should they pay to send your child to UPT and FTU and ZERO AF flight hours over my DS that has proven himself within the AF?
3. Let's assume he is one of the few that goes this path (Guard and Commercial rights our the gate). As you know it is a line number issue. He will start in the right seat and move to the left which is true for both the Guard and Commercial. Now here is the problem, which is tied to my #2 point.. Why would an airline hire your DS that has fewer hours than my DS? Both would be paid the same, but my DS will have 11 yrs of flying, and your DS has 2 or 3?
4. Many that go the route he is thinking of will start on what military people call puddle jumpers. Great example, DS lives in Abilene TX (Dyess AFB) we fly there 2-3 x a yr. The plane carries maybe 75 people, it is basically up, down and land, repeat. It is not glorious at all. To get to the next level they have to accumulate the hours for multi-engine.
5. As stated by kinnem, plus me, the commercial airline world is filled with ex-military and in the corporate world we would call that networking. He will have very little network compared to somebody that did 11 yrs ADAF even if he is in the Guard. Guard/Reserves are filled with weekend warriors on various weekends it is harder to network than compared to the ADAF member. Main reason why is the bonding that occurs throughout their careers.
~ My very best friend in the world husband flies for SWA (South West). The 1st time he saw him after winging, he shook his hand and said welcome to SWA....in 10 yrs! Our other close friend is now a United pilot and he said the same thing. A third close friend is with FedEX. IOWS, he not only has our connections retired AF), but he will have his connections through his time as an AF pilot.
6. If this is his goal, why go to college at all? Spend the money on getting his multi-engine rating and start sooner. My very best friends' DS only has an associate degree. He has now decided that he wants to be a pilot. He is getting his PPL, but knows he will need multi engine and the ATP. It will take several years full time. I saw him a few months ago and we joked that by the time he gets hired on and moves up the ladder, both my DS and him will both be right seaters with SWA. The difference is my DS collected a very nice paycheck, and at the same time bought a home, invested money to use when he takes a pay cut to go commercial.
7. Nobody can predict the future. Currently the AF is losing pilots left and right. The 6 figure bonus that they offer is not enough to keep them! However, your DS is maybe 17. The airlines predict that they will be hiring at this pace for about 5 yrs. and than they will slow down. See all of the points above.
~ FWIW, if you have investigated why there is a shortage, than you know that it is tied to 9/11 and the FAA age requirements for commercial pilots. IOWS, they didn't hire pilots for a decade, and due to the FAA the majority of these pilots are now ageing out, hence the need to replace them. Now add in the fact that about 70% are leaving the AF. the airlines will be able to fill their slots, while the ADAF will be short....see #1 regarding why would they allow him to go Guard if ADAF is short?
Finally, ERAU is great, and no offense to them, but it is a dang gone expensive school. I am a long time poster. It is true after USAFA has the most rated positions handed out. The thing is that is a number, not a percentage. As an old poster I would advise you to ask the more important question: what is the percentage. The yr my DS commissioned they had a 93% national rate for rated (Pilot, Nav, RPA and ADM), but ERAU was below that percentage.
Sorry for the novella, but I think you need to the big picture. Good luck