Hi BBD62 and welcome to the HSBBW. Congratulations to your son for getting good early interest. You have already received some good advice from TPM and Hr04.
I wanted to relay some information related to your situation. I know a boy that received an offer to a top D1 SEC team while he was recovering from TJ surgery (not my son by the way). So if the teams know about you, have seen you and or get great reports from scouts you CAN still get the offers. Just be sure to get the pain diagnosed correctly and set out on a complete recovery program. It might help to have copies of the doctor’s assessment of elbow tendonitis to give the coach if you are visiting colleges this summer while recovering.
I would plan unofficial visits or contact by phone or e-mail to the schools you are interested in (on your top list) and more importantly, the schools that have already contacted you that you might be interested in as well. While on any of these visits (or any other forms of contact you choose) to the schools that already have showed interest in your son, tell them about your situation for the rest of the summer in case they were planning on seeing your son this summer.
Could become difficult to walk that line Hr04 was talking about between too much information and not enough. If the schools are looking for your son at a specific event and he is a no show due to injuries the coaches may be wondering what is going on already. You sure do not want to feed that fear with little to no information.