Based on the information here, I would say your son has very little to worry about. He sounds very talented, and he will be fine. The average ACT Score for the 75th percentile of students accepted is a 31 which he is well above. However, I know very little about your son and how well a fit he would be at the university or how good of an essay he writes. But from the sounds of this for, Texas A&M University, your son is an extremely well qualified candidate that has an extremely high chance of being accepted. (I would highly doubt that he would get rejected.)