Earlier quoted context omitted.
Just reporting what I found, I think the guy is on thin ice. If the company treats him well though, he will be fine.
"Thin ice"? I doubt it. As long as this has nothing to do with his employers business, he's probably fine. Remember even if he's technically in "violation", the company has to care enough to go after him. Most of the time it won't be worth it.
Every large tech company I worked for has been crystal clear during orientation: they own everything I do... on my own time or on theirs, using my own equipment or theirs. There was no ambiguity. Maybe his former employee is more chill. Maybe they won’t go after him. Maybe it won’t be worth it. That’s a lot of maybes to hang your livelihood off of.