My very unmotivated nephew wants to go to college

Building trades are desperate for young people to get into the business. Might be a good alternative for a C high-school student.

By that approach: yes.

You can only offer him advice, support and encouragement, for a start.

You've not said why he wants to attend college - perhaps he is fed up with being a school-boy and wants to learn in an adult setting, i.e, a college.

Though obviously if he cannot decide what sort of career he wants, simply going to college won't really help him unless he knows what subjects he is good at, and wants to follow those.

Pushing him into work won't help either if all he can find is unskilled labour on poor pay and conditions, and it will make it harder for him to attend any training course.

Either way he is stymied, but are you missing the point that perhaps secretly he does know what he wants to study, and how, but won't admit it because he feels pressured and demotivated by others trying to make him merely "figure it out"?

Figure what out?

I doubt he knows that unless you tell him! Is anyone helping him? Or are they just making him defensive and pushing him further into his shell?

You aren’t wrong 🤷‍♀️ but yk how it is sometimes when you tell the truth

College used to be where one figured things out and decided what they wanted to do, not the workplace. College, or a trade school. If his parents are willing and able to pay for that foundation, it makes more sense in the long run and will give him more options in the workplace rather than a dead end job.