I am not in fact a wrestler myself, but have been an athlete all my life. The most difficult thing with a pump and high intensity/ high contact sports is getting the pump site in the right location. Things to try:
1. Avoid high muscle areas, if possible (abs). In my experiences, muscle pushes the catheter right out, especially when sweating.
2. If high muscle areas are unavoidable, consider a longer catheter. There are some catheter options that are up to an inch long and can go in diagonally. These anchor better in dense muscle areas (anywhere for that matter).
3. Regardless of what infusion set you use, tape is key! I found that when I placed a layer of tape on my skin and then put the infusion set in on top of it, it stayed a lot better. Also, once i had inserted my site I heavily taped all around the area. This might seem like overkill, but it really helps to spread out the tape so that at least some of it might be attached in areas of lower sweat.
Wrestling (any sport) is definitely possible!!!!! I have known several very very successful diabetic wrestlers, some who pump, some who don't. If you start having a lot of trouble adjusting to the pump during the season, it may be a good idea to wait until he is out of season, or at least in a less intense sport.
Good luck to you and your son!