Anyway, if I'm understanding it right,
1. Your son had your phone and laptop
2. Your son sent an email to a certain link which came from his mom
3. The link connects to a boyfriend of your ex
4. Then weird stuff started to happen
Considering that you yourself admitted that you aren't very tech knowledgeable, I'd suggest getting an external hard drive and making a backup of everything too important to lose from your computer and phone, then basically format them both. You can sell them and buy new ones, or make sure they are really flashed clean (new HDD for the computer, and an OS flash for the phone).
If no money is gone, not sure if there's anything you can go to the police for.