I'm totally in the back off camp, and lightening up about his reading choices.
For a long time, our bedtime routine was that I read a chapter of a book to the kids, and then they had 3o minutes of "quiet time" in bed before lights off. They could read to themselves, draw, or have their lights off. Both my kids developed a love of reading and decent drawing skills!
Some graphic novels are very, very good. My 15 year DD really loves "The Watchmen" and it helped get her interested in history. She is in highschool and in pre-AP English, and most of her gifted/advanced peers -- especially the boys -- like quality graphic novels. When my kids were young, it was normal for them to flip back and forth between reading material that challenged them and reading material that was easy. When she went through a very stressful period last winter, she dug out some books she had really enjoyed when she was 10 (Warriors) and reread them. It was comforting to her. This summer she has taken on books she has heard of, but never read, like Clockwork Orange, Animal Farm, etc. I really think if I had pushed her last winter when it looked like she was regressing, she wouldn't be reading what she is this summer.
I don't understand the thing about math. I would let it go, which would be better for your relationship with him and his long term feelings about the subject. Do fun things with him. Besides, a lot of life has math built right in.
As far as teaching him to work at something even when it is difficult, I agree it is important, but I doubt that it can reasonably be done with respect to academics at this point in his life. It could be in another venue, such as sports or music. I suggesting helping him find something that he likes well enough to work at it. For Miranda's kids, it was music. For mine, it was swimming.