Well, the fact that some came to see his HS games points to some interest. Those that stayed in touch points to some more interest, although still not "love" if they haven't acted on it. Those that didn't stay in touch points to less interest.
You asked... "Do you want to give them one more look?"
I don't think there are always definitive answers. Does the player have more to show now? Does school have a need now that they didn't have before? Etc., etc.
I think the camp event makes for a good discussion point for him to call prior and ask some pointed questions and try to get some clarity where he stands with a given school. If a school is on his list and there has been some dialog, he can call, tell them he is interested in the school and trying to line up events with schools who are mutually interested in him but can't afford the time or money to go to events where there is no real interest. Where am I on your board? Does it make sense to come? If so, will you be able to show me around the school a bit and talk in more detail about where you see me fitting? I think these types of questions prior to the events will tell you much of what you need to know.
The "go where you are loved" mantra is preached hard here and it is a very good one. But, I believe there are an awful lot of good players that can contribute at the college level that won't get clear love in their recruiting process so it isn't always that simple. But, still, every effort should be made to know exactly where you stand before you commit.
I certainly wouldn't recommend going to a camp without having some previous dialog with the RC or HC. Although of course, if the player shows up at a mid level school camp throwing 89, decent secondary stuff and command, he will turn heads.
As a side note - this is probably for others more so that you since you have already attended some of these... be careful to identify and separate "prospect" camps from regular camps. Sometimes, the line is fuzzy but most often, colleges will have one or two true "prospect" camps where the intention is to bring in players who have the ability and are of the age to actually get a look as a prospect for the school. With these events, it is fairly common that a few or many have been specifically invited and there are meetings set up around the actual camp.
Then, they will have general camps where players across a wide range of ages and skill levels can attend. These are more just to raise $$ for the program.