A harraser that won't stop contacting despite being asked to stop

Edit: Thank you, everyone, for your responses. This has given me confidence to assure her that involving the police either directly or through a trusted relative is the best option.

Some were wondering in direct messages why she was patient. I kept assuming to avoid family issues, which is partially true, but she just informed me that she has known people who got their brothers/sons deported because of similar issues and they were suffering. She didn't want his family to suffer because of his actions. She is dumb to be considerate towards such a horrible person...

I will be disposing this account soon. Sorry in advance if I don't answer any inquiries.

Original post:

A female colleague was harrased by a guy from different numbers, he wanted to propose to her but got rejected nicely. He kept contacting despite clearly asking him not to. He only stopped after a colleague met him and forced him to stop and

2 years past and somehow she forgot to block one of the numbers he used to contact her through on WhatsApp. He saw a recent status of her and just said hi and started giving her updates as if he was never asked to stop contacting her!

Now she blocked him on all numbers and deleted the contacts. She used to keep them saved as spam1 spam2 so that she will know that it was him if he tried contacting from other messaging apps. Just now she realised that as long as he is saved as a contact, he will be able to view status on any messaging app that she didn't block him on.

If he decides to contact her from a 3rd number, she will - finally - report him to police. She is concerned because she doesn't know if this will stop him forever or if this will make him want to take revenge.

We can't figure out his motivation. He knows the laws of the country very well and knows what he is doing is wrong. He was asked clearly not to contact her at all by her and our colleague. He knows she is Qatari, and what he is doing is against the traditions of the country.

Is he trying to get her pissed so that she will say something bad that he can sue her for? Is he just disturbing her as a punishment for rejecting him? What is the best approach to scare people like him?