Friend lighting up moons like we're on Jupiter

Jupiter, the planet, not the company xD

Okay but seriously though, my friend who works at a startup, is also in a freelancing company (all remote). He asked me to contact my ex company for a possible referral....and that he's actively looking for a 3rd job.

I mean work wise, I'm pretty sure he's using AI tools to work on 2 (now possibly 3) jobs. But won't companies find out, based on his form 16 (I'm kind of a newbie on taxation)? How do companies not realise this or is it that companies can't really find out (?)

Explain in detail how to pull this off :3