My son is also a RHP, not as tall as yours, similar velo, went to HF summer after soph year in 2018.
HF is very well run and was a great experience for my kid. He got to talk directly with some coaches, got some good advice about the recruiting process from the HF folks. In my opinion, the expense was worth it.
BUT, if you are evaluating things strictly from a recruiting standpoint, you may want to wait until fall or next summer. Your son’s stats will get noticed. However, D1 coaches can’t talk recruiting with 2021s until after Sept 1. Based on my son’s experience, D1 coaches will not say more than “Good to meet you, but I can’t discuss recruiting with you yet. Keep in touch.” (Granted, if your kid is good enough and a coach wants him, there are plenty of ways around this. My son was not in that position, although he got some emails and texts from D1s at and after HF.) The D3 HA schools generally don’t recruit until summer after Jr year. Son met several coaches and had some good conversations. IMO it can’t hurt to get on the radar even in a preliminary way, and son continues to correspond via email with several of these schools. But for D3 schools (most of the colleges at HF), summer of 2020 will likely be more directly productive for your son. I think it comes down to your time and budget. It’s a significant expense. It’s also a chance to take a trip with your boy and spend some time together (although HF is not in a part of Long Island that I would choose to vacation in). Know what the return on your $$ is likely to be, then make your own evaluation.