Restarting Mac after Scammer Had Contral

So ... my mom had an Apple Care virus alert pop up on her browser window and called the number. She then allowed them assess to her Mac Mini (she clicked on something and then typed in the password to her computer). When they asked for money, she called me and I told her to immediately hang up on them and unplug her computer.

My question is: What do I need to do when restarting her computer? Change the password, of course. Is there a malware sweeper program Apple recommends to check to see if they downloaded anything on her computer. Anything else I need to check?

TIA