I will be honest if DoDMERB said he would get a waiver, that is bad gouge. Not sure if that is who told you that, but if it was, that is just simply bad info that they should of never said. The commissioning source issues the waiver, not DoDMERB and it was out of their swim lane to state that. USNA has an extremely limited number of color waivers. The rule of thumb is up to 20. I am not even sure they have hit that number the last few years. Waivers for color blindness are in more abundance at USAFA and USMA. An LOA means USNA definitely was interested in your DS, unfortunately that is a tough DQ with a capped waiver. Best bet is after the dust settles in admissions to call his admissions rep and discuss reapplying. If he has interests in the other SAs might have a better shot there. Good luck to your DS, an LOA is no easy feat.