It is not only FAIR, but you are doing him a big FAVOR. Hopefully, he will one day appreciate you for it. Hopefully.

Look, I abridged your post just to highlight core issues. If he does not see that (1) is WRONG (he does not see it, per (2)), but you see that (1) is wrong, you then find yourself being the only person able to see that something is wrong. He needs to figure out that it is wrong and to get help in order to live a happier life and to gain social acceptance in college (as you are certainly well aware of, college years are not just about education, but also about figuring out who you are by yourself and within your social group).

Then, you used whatever leverage you have as a parent paying for his college to induce him to make the right step in seeking evaluation - (3). So you are being more than FAIR - you are being very KIND and SUPPORTIVE.