If a software analogy is what you want, it's like he used some third party library which requires a license to make new software, but didn't pay for the license

If a software analogy is what you want, it's like he used some third party library which requires a license to make new software, but didn't pay for the license. Sure, the code is new and unique and his, but it contains the code that is patented. Doing it by mistake is one thing. But he clearly did it on purpose and was trying to win in court to get away with it.