bonnie - I can see where you are going with this and it is a good question.
I would hold off sharing that card with the coach just yet. If you would like your son to attend Pitt, it might be better to have him attend several of their camps and first see if he can get an offer. If they call and offer a scholarship or recruited walk-on, then you can let them know how your status there can possibly help their program out. After attending their camps and you still don't get any interest, then it might be worthwhile contacting the coach and notifying him of this fact and see if that might in fact generate some interest.
The fact of him having other money available via the tuition discount will not provide much sway unless they see him first as a contributor to the program imho. It is kind of like a kid who has perfect SAT's and a perfect 4.0 GPA. It sure won't hurt their chances but at the end of the day they will have to first and foremost convince the coach they have the talent they are looking for.