For Cornell, Yale, Duke, and Harvard the biggest problem is that the large majority of applicants are fully academically qualified to attend, and the acceptance rate is very low. I think that you just can’t know whether or not your son will be accepted to one of these schools.
Students frequently under-appreciate their in-state public options. UT-Austin (if that is the one that you are thinking of) is a very good university.
I think that your son’s profile is interesting and somewhat unique. This is likely to be helpful. I think that he is likely to do very well wherever he ends up.