We were given a brief about this, and if I can recall correctly, he will have to do STAP if he is on the lower level math track.
-1337BeachedWhale1337
That sucks and is definitely a change. If you were in rock math and didn't fail, you just took an extra semester of math to finish your requirements than the people who weren't in rock math.
I did voluntary STAP. Only certain classes are offered, depending on demand and availability, and its hard to make it into them as they usually save the slots for Corps squad or those who failed the course during the academic year. That said, it was a great way to knock out a 3.5 credit course for me that I didn't have to take during the school year. Have your son find his DAC (he can find them by either talking to his TAC who will know who is assigned to the company for those without a declared major or by checking his CIS academic page where his grades are).
Only thing to be aware of is that his DAC, until he declares his major, is probably going to be from some completely random department that may have no idea how the courses work in his desired major. I ran into this issue but thankfully had a family friend teaching in a department that did line up with academic interests who was able to sit down with me and go over how to organize my course work before I met with my DAC. It led to a much more productive time with the random DAC (who will only be your assigned DAC for 1 year and odds are 99% likely, unless you fail or have something weird going on, you actually will have zero interaction with) in setting up my schedule to allow for voluntary STAP as a rising yuk and advancing courses forward my yuk year to start my major a semester early.
It helps to be proactive as possible with your schedule. If you son knows what he is interested in majoring in, he can reach out to that department (have him ask an upperclassmen who is in the major to assist in getting him to the right people to talk to) and they can help out similarly to how my family friend worked out my schedule.
That being said, if he has no clue, not a big deal. He has another semester or two to figure out what he wants to do for his major and even then, he has the possibility of changing it if it doesn't work out.