Copyright law pisses me off, it's gotten way too strict and powerful, and is only a benefit for large companies to bully small guys and killing their many hours of work. The penalties are also way over the top, so people feel no choice but to just comply as it's not worth fighting. It also costs a lot of money to fight. You're better off committing a real harmful crime than being found in violation of IP laws. It's also very easy to be in violation due to how broad some trademarks, patents, etc are. For example there was this youtube channel that decided to trademark the concept of reaction videos. It actually got approved and everything, and they started sending takedown notices to any video that had the word reaction in it. Eventually they stopped due to the backlash, but law wise, they were in the right and could have easily kept going.
Sadly even though he may have coded this 100% on his spare time, lot of companies have very strict clauses about conflict of interest. Some even own anything you do even if it's on your own time. Some it's even for life. When you are a new hire at a company you'll sign anything you have to because you need a job. They put these clauses in there and whether or not you agree or even read them... you do need to sign to keep that job and pay the bills. The company I work for has clauses like that, anything I make, even on my own time, they own rights to it. I never heard of anyone actually getting nailed by it though. I think it's more something they have so if they ever need to, they can persue it.