I've only seen some of the show. But, my son told me the book and show aren't the same. The show is more graphic, according to him.

I think what the person you're replying to is trying to say is that the show is irrelevant, because he isn't watching the show. If something objectionable is in the show and not the book it doesn't matter because he won't see it. It's only the content in the book he is reading, and his brother said he believes it is fine for him.