Some of the things I have read him being accused of plagiarizing are not really original. They are stuff that at least thousands of different people in a city can come up with at the same time if they give a thought to it. So it is very likely that he comes up with them independently. Or at times he gets influenced by other writers something that all writers actually do from time to time if not all the time.

And then those who accuse him also forget that copyright protects the expression of an idea not the idea itself.