There are a ton of soccer camps out there. The ODP camps at the Thacher school come with no guarantees, but I can say that they do involve many of the coaches that scout for ODP and some that occasionally coach a regional ODP team. So, from that perspective, your son may have exposure to them in a way that he would not have at another camp.
However, this does not mean that he will be recruited into the ODP pool. It just means that he would be seen by coaches that are involved in the process. It also means that he'll be coached by them a bit over the course of the few days he is there, which could be a good thing.
I'll share a couple experiences:
My DD went to an ODP day camp one summer for a week. She enjoyed it, but I think the pacing of moving from group-to-group working on different things seemed too fast. There were a ton of kids and it seemed like the player to coach ratio was high. We didn't do that again.
We heard decent things about the ODP residential camps and she attend one and thoroughly enjoyed it. Part of it was getting to hang out on her own with some friends at a residential camp. However, we also noticed (at ulittle) that she came back very motivated to work harder on her game. They have sessions off the field where they focus on the mentality of the player and she benefited from that. I also noticed that the coach to player ratio seemed better than the day camp. I would recommend this camp, but it isn't cheap and your expectations should be reasonable.
Just last year DD attended a residential training camp at a college. The training was largely coached by the college players with some involvement by the head coach and assistant coaches. Pretty mixed bag in terms of quality, but DD definitely remembered the coaches. In the fall, she recognized some of them on the field (PAC-12 tv) and the head coach of the team. So, she was excited about that.
Of these experiences, I think the Thacher school residential ODP camp was the most expensive, but DD probably had the best experience there. Her experience wasn't positive because of any ODP links, she just liked the atmosphere and she noticed many other players on teams she competed with were there. She still sees girls she met at that camp out on the fields. With that said, it isn't for everybody. If you want the exposure to lead to an ODP call-up for your son, then you should temper those expectations. It's not impossible, but it shouldn't be expected.
Aside from the ODP link, I think some of the colleges here in SoCal put on weekly summer soccer camps that can be reasonably priced and well run.
Hope that helps.
