If your son was accepted to WP, he is likely competitive with the others. But the competition within the moc slot is likely going to dictate what happens with the other schools. My son got USAFA and USMA appointments very early a couple years ago, then , after thinking USNA gave up on him, he got a phone call and offer of appointment there too, but it was only days before we were heading to R-DAY at WP, and USMA was his first choice anyway so he passed.
Staying in touch with the admissions officers is important, and hopefully they can provide some insight.