Sims 3 University Life- Sim Won't Go To Class

@GBAD0486  Have you tried replacing the building(s) where your sim is supposed to go to class?  You should be able to find them in Edit Town.  Load the save, let the in-game clock run for a few minutes, then use "save as" to rename the save, so you can experiment on the new copy while leaving the original intact.  Delete the building where your sim is supposed to have the next class, and place a new copy.  Then save, quit, delete the cache files again, reload, and see whether your sim goes to class.

If this doesn't work, there are mod-related solutions you can try, if you're interested.  Otherwise, I'm not sure exactly how to fix it directly.  But you could also have your sim study for a day or two while missing classes and see whether he's gaining enough progress to suggest he'll be able to pass.  If not, dropping out and reenrolling might be the better approach.

By the way, do you have a save from before your sim started this term?  When something like this happens, I tend to think there's a problem with the world overall, even if it's small, and I don't want to work around it so much as fix it or revert to a previous save.