He has a right to be angry but the situation is very complicated.
1) it is unrealistic to expect the same position coach will be there through your college experience. You pick a program for a head coach and the university. The Head Coach is important because the position coach will coach to his philosophy. Brady Hoke leaving Michigan is much more important to the team identity than Drayton leaving Ohio State.
2) on the flip side, you do not want to misrepresent your brand. If Drayton told him the night before signing day that he was definitely going to be there that is a problem. If he said he would be there his entire time at OSU, that is a lie as well because we do not know what tomorrow will bring. You do not openly misrepresent yourself in such a case. If it came down to Drayton, and he lied, it stains the program.
3) Even if you are in the right, the PR by this could be bad and you need to take care of your brand. If the kid comes protesting and putting up a fight, you have no choice to let him out of his letter and let him go to Michigan. If the kid ultimately wants out you need to let him go. If there is miscommunication, you err on the side of the 17 year old. If you force him to honor the commitment, it will ruin the relationship with coaches up in Michigan as well as potentially other schools around the country. This is bigger than Weber as it effects the brand.
4) Weber, has a right to be pissed right now, but if he calms down and takes a week or so to let it sink in, he will probably see that while Drayton was a key to him going to OSU, he picked OSU for many more reasons beyond Drayton, and outside of that minor component of Drayton leaving, the place is the same place that he fell in love with when he committed initially.
I am sure with a few days rational minds will prevail.