My neice, who was supposed to graduate May 8th, took 18 hrs this semester, has just been told she can't graduate. Two of the classes the advisor set her up with, will not count.

How the F does this happen???

What is the best recourse of action here?

I would visit with the Dept. Head. I doubt it can change her situation, and the DH has been probably already been alerted to the situation. However, I would follow up with them to explore her options.

Depending on which college, some advisors are employed at the college level to work with specific depts and some depts that are large enough may have their own advisors. Find out who the Assoc. Dept Head for Teaching is in her dept. and go directly to that person. Lay out her case and ask about the possibility of substituting the classes she was told to take by the advisor for the classes she is evidently missing. Copy the Dept head. That gets the ball rolling with people who have some authority to look at what happened and possibly figure something out and get back to you with some type of decision/response. Above the Dept level there would be some type of Assoc or Asst Dean of Teaching that is supposed to be managing all this type of stuff for the college.

Agree and if they don't do any of that ask if she can still walk in May and then take that class in the summer. I know not ideal but it might not sting as much.
Sorry that is happening to your niece, advising at the high school level all the way through college needs to be fixed

I appreciate all your responses here. I've passed them along to my neice. I'll report back if she makes any headway.

A&M definitely needs to hold the advisors to higher standards or find some way to weed out the incompetent ones. There are some who are exceptional, love helping students, and really know what they're doing, but there are others who have no clue what they're doing.

You may reach out to Bonnie Bustos-Rios -- https://studentsuccess.tamu.edu/about-us/meet-our-team/meet-our-team/bonnie-bustos-rios

I know her professionally, and she's amazing. If anyone could help, it would be her.