No need to panic Coolred38!
Your son has passed day 1 assessment, which was the hardest part. Now that means he was more than halfway through! For day 2, unless he has shown some terrible attitude or given totally irrelevant answers to specific questions, he will be just fine and likely to be selected.
For the total number of cadets who have been interviewed, they were surely more than 7 by far. It's true only 7 have made it during the first few days, but later on, more cadets have passed too. What I know is that the first batch will be around 20 cadets. On a latter stage, there will be other batches to follow. So if he wasn't selected for the first, he might catch the second I guess. Another thing, which is of my own assumptions and may not be true, what if they have done some sort of ranking of the guys who have passed. If this is the case, then just passing the tests and the interview won't necessarily mean that an applicant has secured a seat!
The good thing is that they have never told your son that he has failed or will not get a chance at all to join. May be they are keeping him for the next intake. Let's say his status is "pending"! That's not bad at all to be honest. Many applicants didn't make it, and they were never contacted to know why!
I know how your son feels after all. But try to discuss it with him positively (and you are not faking anything though!!). Patience is his asset now!
All the best
