Great question, and one I hear in various forms from time to time. In short, my recommendation is to NOT force him to go on the scouting trip, and here is the reason:
In general, there is a lot of anxiety surrounding this event already in the boy's mind (you actually wrote quite well about that above). If the issue is "forced" and you make him go, you will be essentially shooting his anxiety right through the roof, and either (a) a power struggle will ensue, whereby nobody wins, or (b) he goes because he feels he has no choice, and he melts down on the inside, anxiety making him miserable.
And I recognize that there is a possibility of a (c), that he goes because he is forced, has a good time, and forgets all about the separation anxiety he experienced before the outing. I totally get that... but it is less probable than one of the other two possibilities. It is the equivalent of a parent of a shy kiddo forcing him/her to speak in front of a crowd or go to a party alone... you really want to minimize the toxicity of the event, and if the child is extremely anxious, odds lie on the side of the negative.
To deal with this type of anxiety more effectively, we should try to avoid "flooding" him with anxiety, and instead "trickle" it onto him. Allow him to do structured events that are short in duration (without dad) to get him accustomed to being separated. If this proves to be too difficult, have dad move away a few steps when he is with his friends. Do this a few times and then have him go out of sight, but still nearby. After awhile, have dad "run an errand" to the store or something while the son is engaged in a pleasurable activity at camp.
I think you get the picture. This is called managing anxiety through successive approximations, and helps the kiddo keep a lid on escalation while he is gradually gaining a sense of self confidence.
I hope this helps! If you are satisfied with the response, please hit "Accept." This is the only way I can receive credit for my answer. Thanks-