I can see where you're coming from, and I certainly agree with it in an adult context. But, and it's difficult, I think it has to be balanced against the problem of how teenagers cannot - in part, physically cannot - make good judgements about their future. Parts of the brain that deal with risk supposedly aren't fully formed until 25, for instance, and there's almost certainly (inherently) no life experience of long term opportunity cost. So what else can you do but exert authority? Which you pretty much can do as a parent, within some parameters and with varying degrees of success.
It's not ideal but grudging, half hearted compliance might be enough to carry you through to self-realisation, acceptance and personal buy-in. It's not the preferred route by any means, is it, but you have to balance the imperfections of that against the stuff I said earlier, that things get difficult if you miss that boat.
Well, yes - you can't leave a vacuum. But I'd always think that friendly guidance - even
firm friendly guidance - is going to be better than enforcement.
After all, one of the life lessons we are trying to teach young people is that they will, one day, have to make these decisions for themselves. They need to develop the emotional muscles to be able to do that, and if we simply insist (leaving aside for the moment the likely success of that) that they do things a certain way, all we are really teaching them is a kind of binary conform-or-die lesson which may achieve compliance in the short term, but leaves them without the skills to be able to make the judgement calls we might be making on their behalf when we're not availabe to do that any more.
One of the techniques used in working with addictions is motivational interviewing (MI). A key mantra of that approach is to "roll with the resistance" - ie., to let the client (the "addict") explore for themselves, with you, their reasons for not changing (incidentally, the best suicide interventions do exactly the same thing - have the client explore, in depth, all their reasons for killing themselves). The argument behind this is that, if the client is given the space to think about the issue freely, rather than being bombarded with instructions to do this or that, they will be able to come to a solution that they can own, and which is theirs. I think that encapsulates your point about helping adolescents make their decisions: the only difference is that, from my point of view, it is far better being done collaboratively.
There's a risk: they might not. That might be because they're already in the truculent resistance stage where they're happy to cut their nose off to spite their face, so long as it means they're not complying with something they feel is being imposed on them. Or it might be because, at that point, they simply don't
want to change. That's when we need to lean back (slightly) and take the pressure off.
To go back to the OP's challenge - it's very likely that the college has some kind of counselling provision. Rather than try to solve this problem by yourselves, it may be better to work on encouraging this chap to consider exploring what's going on with an independent third party, like the college counsellor. If not that, then there may be a tutor or coach whom he trusts, and who he might be encouraged to go and speak to about what's going on for him. The hard bit here, for parents, is letting go and trusting that someone else (including the OP's son) has the ability and resources to be able to solve the problem without the parents' direct involvement.
I have seen this kind of approach pay dividends; on the other side of the equation, I've seen what happens if it's not done: I've just had a message from a client who was in college, but doing what they felt were the wrong subjects, and who succeeded in getting thrown out of college for possession of cannabis - something I suspect was, at least unconsciously, engineered by them to "solve the problem". In the process, their phone and laptop have been confiscated (their call to me to say they couldn't continue to see me was in considerable distress and made secretively from another phone when their parents were out). That client has achieved what they wanted - they're no longer studying subjects they didn't want to do. The cost of that decision is high, as they're unlikely to be able to return to college again, and I firmly believe that the situation was vastly escalated by the parents' decision to take the enforcement route - which has clearly failed - rather than engage with their offspring to address the underlying problems. There would still have been room for firm guidance, but in the absence of this level of coercion (or, ideally, of any), the student might have been looking at a wider range of options.
And we were doing some good work, and making a bit of progress towards more constructive solutions - all now lost.