As he said, he did not want to burn his bridges.
If you can prove it's your invention, and they're distributing it without your permission, they won't want to waste money defending a suit.
You may be a little guy, without enough dosh to launch a suit; but you could sell your interest to $COPYRIGHT_TROLL, then they'd be in trouble. So just ask them nicely to propose a settlement.
It's not like war, or anything; tech-company legal departments are there for just this kind of thing. Unless there are arseholes involved, it can all be friendly and business-like.