I remember how hard it is to wait.
My son was on the NWL back in 2006.
It is really impossible for anyone outside of admissions to know what his chances of getting off the NWL are. It depends upon where your son is compared to others and how far down the list they get. If he can talk to his admissions officer he may get a better idea of his chances. While he is waiting he should update his file if he gets any new awards, leadership positions, or athletic letters. Every bit helps.
If your son would be open to the option of a civil prep scholarship from the West Point AOG he should tell his admissions officer. My son was open to this and ultimately was offered this option. In case you don't know what "civil prep" is I'll explain. It is usually offered to candidates who are fully qualified but may not get off the NWL that year. It is a partial scholarship for these candidates to attend a military junior college (New Mexico Military Institute, Marion Military Institute, or a few others) for a year and reapply to West Point. Not many of these are offered, back in 2006 the number was 65 but that can fluctuate. These candidates who do well at the junior college, stay out of trouble, and reapply have an excellent chance of being offered an appointment the next year. The quote I have heard is "it is their appointment to lose" which means an appointment is reserved for them the next year but if they screw up in civil prep then no appointment.
My son did his civil prep year at New Mexico Military Institute and was accepted into the class of 2011. Yes he complained, and still does, about that extra year but in the end it got him where he wanted to be. He could have taken the 4 year AROTC scholarship he was offered and ended up being an Army officer, but he was willing to do that extra year for the chance to go to West Point.
If you have any questions about civil prep just let me know. I almost forgot...even if a candidate accepts civil prep they stay on the NWL until R-day. So it is still possible to get an appointment even after accepting civil prep.