So, if you're the parent of a young-adult (notice I didn't say child) in college, should you even try to help out your son or daughter by giving their professor a call?
No, no, no, and no.
Here's an article from U.S. News & World Report on 10 Reasons Parents Should Never Contact College Professors.
There's another reason too. At my institution, we've been told we're not allowed to talk to parents, not even allowed to verify that their son or daughter are even registered in our classes, because of FERPA - the Family Educational Rights & Privacy Act. The only exception is if a student goes to our Registrar's Office and fills out and signs a waiver.
So, when a parent calls me to discuss their little darling, I just tell them "Sorry, due to federal privacy laws, I'm not allowed to talk to you about this." Many parents view this as horribly unfair, especially when they're the ones paying for the tuition and books.
But, to be honest, most parents who would call a professor are not the kind of parents who'd want to hear my honest appraisal of why little Jimmie or Katie is failing my course. It's a community college, virtually all the kids who attend are smart enough to pass the 100-level courses. If they're failing, it's because:
1. They don't come to class
2. They don't give a shit and aren't putting any effort into the course
3. They don't turn stuff in
It's not rocket science.