Is that the Showball in Cali? Has he created a short list of top schools he's interested in there? Most of the kids are going to spend a lot of time talking to Ivy coaches. Make sure he contacts the coaches he's interested in ahead of time and fills out their recruit form. By the time my son went he felt like he already knew the coaches and it was a very stress free conversation. Didn't feel like he had to make a first impression (besides a firm handshake, eye contact, etc.).
IMO, Showball is geared much more towards pitchers, which is great if you are a pitcher. Make sure he has a good warmup/bullpen plan. A lot of coaches will watch that, so make sure he is focused and throws everything while warming up. Catchers will also get attention. Fielders will need to hit bombs in the scrimmages or post a good 60 number.