There should not be any filter on him because of laser surgery. During my time on the Surgeon General's committee on aircrew medical standards, the 'no laser surgery before OASC' policy was amended to recognise both advances in surgery and the potential for turning down potentially the best pilot to ever walk the planet because he or she had been treated prior to their medical. The argument used to be that accepting previous laser treatment meant you could be encouraging someone to have surgery on a healthy eye when the probability was that the candidate would trip up on aptitude, anthropometry or their officer qualities.
My recommendation is for your son to do the aptitude tests as a stand-alone (test in advance) - OASC can do this and his UAS will be able to help set it up. He would then be in a better position to decide whether he wants to have the surgery purely to meet the medical standard. He also needs to know what the odds are of securing a pilot slot, as it is a very competitive field for a small number of places and there are some extremely talented young people out there; I hope your son is one of them.