You are a good friend indeed! Yes, predators prey upon ppl of that nature, they can spot a previously abused, and often submissive person quite easily.

I've been stalked, it isn't easy. During that time, my mother happened to see me in my car right after I had gotten into it to leave the store's parking lot. She came up and opened my door of the car: I nearly pepper sprayed her!!! She never surprised me again

I hope she has informed the police already. Does she have time and date written down of each and any occurrence? Does she have a small camera to take possible photos when she suspects being followed? Witness accounts of seeing this man?

Good wishes for both of you. Hopefully, if the man sees she has a strong friend (you) he will leave her alone... but hopefully someone will catch him before he does anything to anyone.