https://fsaconferences.ed.gov/2017sessionlist.html - scroll down & find Session 21. This presentation has everything you ever wanted to know about loan repayment!
Parent PLUS loans do not have IDR or forgiveness options. The only way it might work is if a parent has his/her own federal Direct student loan & consolidates the Parent PLUS loan into a Direct Loan - contact your servicer to find out if you might benefit before doing this, though.