kinnem,
Was he told what the wait time will be like? I know with our DS (AFROTC), as 300's when they got their rated slot were told as much as 6-9 months for their 1st school (IFS) date if they were not given casual status. They were told typically 3-5 months wait time if they were given casual status, but their class date for IFS would still be 6-9 months either way. Thus, like your DS none of this was a shocker for the cadets. DS worked at a major retailer during the summer to save more money.
One thing to keep in mind is if they have taken the career starter loan because the payback is like student loans, 180 day grace period from commissioning.
As you said the big reason is the pipeline flow. In his UPT class it is a mix of AFA grads, AFROTC and OCS, and he started UPT in April.