Tech is a STEM major like engineering. Non-tech would be majors like business, govt, etc. Understand if he gets an ICSP as a tech major, but after his freshmen year decides to switch to a non-tech major, he will need HQ AFROTC to approve it to retain the scholarship. Chances are very slim that they will retain the scholarship.
Additionally, AF scholarships are considered a 2+2 scholarship. If they are not selected in their sophomore year for Summer Field Training (SFT aka EA) HQ AFROTC can also decide to disenroll them from the program, thus, loss of the scholarship.
Finally, the ICSP board is not a definite. There is a limited pot of money. There have been years here that they cancelled the ICSP because so many actually contracted from the HSSP board the year before.
If money is a factor than really think long and hard about your decision on whether or not he should attend that college. College is stressful enough as an engineering major, but when you add in AFROTC, Xtown, making new friends and the financial fears (debt/need of scholarship), it can become overwhelming for any kid their freshmen year.
When you visit the detachment, call 1st to ask for him to meet some 300/400 cadets that are in his intended major. Plan to meet them somewhere else on campus, do not attend this meeting. If you want the most you should do is go in, introduce yourself and than leave. Cadets are respectful and it would be more like a dog and pony show because you are there than him talking peer (age) to peer.