I was assuming that OP was not boarded on October. If he was boarded but did not get a scholarship, it's just like not having been boarded.
If he was boarded in October, and get a scholarship, but not to his first choice school, my recommendation would be to take it somewhere and work to transfer the scholarship later by staying in VERY close touch with the PMS of the preferred school. Of course, I may be completely off the mark, but this is the consistent advice I got from all the officers my son met/talked with.
Regarding your case, if it is a non binding acceptance, you have nothing to worry about. Even if it was an binding acceptance, note that schools release you from the ED commitment if you demonstrate that you cannot wing it financially. Hence, if your son's ability to attend the school (financially) was predicated on the ROTC scholarship, you have a legitimate cause for a release from the binding ED commitment, and then your son can go to a school that he has a scholarship for.
However, there is a rub. Suppose the school's cost of attendance is $50K a year. Further suppose that according to THEIR formula, your EFC (expected family contribution) is $30K. So, they give you $20K as a financial aid. In this condition, from the school's perspective, you have NO reason to request a release from the binding ED commitment.
In theory, this sounds fair enough. The problem is, in many cases, the school's EFC calculation is very much higher than the family's view of their financial resources. A very frequent source of such a discrepancy is the assets such as the house. Some schools consider these when they determine the family's financial resources. Some schools don't.
So, if you have equity in the house to the tune of $300K, the school may think "great. you can now use that asset to get a home equity loan, etc" However, you may think this is absolutely not a doable option for you for whatever reason.
There are many sources of such discrepancy which leaves the parents with no financial resources they can/or willing to tap into, while from the school's perspective, the family should be easily wing $XXX that they calculated.
I don't know your situation, so I can't say which way. You need to sit down and calculate the EFC using the "school's formula" and see whether you have a cause to ask for a release from the ED commitment.
One last piece of input for you to consider. My son's #2 school's PMS said he has a quota for 2 campus scholarships that are entirely up to him. He plans to make his selection in January. Another PMS of a school on his list said, she will only make her selection for campus scholarship in the fall among the students who have already enrolled in her schools.
I don't know where my S2 got the scholarship in this board (I know he got one, don't know where yet). If he does not get a scholarship to his top two choices, I am going to recommend that he contact the PMS of the #2 school immediately, and see whether he can get a campus scholarship in his school (swap his national scholarship with the campus scholarship).
Another thing to consider: if your son's top choice school is the kind of school that takes students with caliber good enough for USMA, there is a good chance that some of the scholarship awardees will eventually opt for the USMA. If that happens, that scholarship quota will have to be filled in April/May, and I would bet it will go to the student who already got a scholarship to somewhere else but REALLY, REALLY want to come to that school and transfer the scholarship. You need to show a LOT of love to make this happen.
My son's #1 and #2 schools are kind of schools where top 25-50% of the admitted students are good enough/competitive enough for all the service academies. As such, I think there will be some spots release in April/May when the students who were accepted into the service academies will jump ship. In fact, the PMS of the #2 school told me that last year, out of 6 national scholarship winners, 2 jumped ship in favor of the USMA and he filled those positions with students who won the scholarship to somewhere else and wanted to transfer their scholarship to his school.
Good luck.