I can remember reading back when JK Rowling was writing Harry Potter she had such bad writers block writing the fourth book and was under so much pressure to finish something she considered breaking her arm to give herself a break from writing. She didn't end up doing anything that drastic, thankfully, and was able to finish the book.
It must be terrible to be under so much pressure as a writer. I don't know how George R.R Martin does it. His series is insane. I don't know how he remembers all the plots and characters and other tiny details of his huge world. He is brilliant at what he does. I could never tackle a task as huge as a Song of Ice and Fire. Hell, in the last couple of years, I have only written short stories because I do not have the energy to tackle anything bigger than that which would involve any world building or research. It takes a long time to write a novel and a huge amount of creative energy and dedication.
George should be congratulated with sticking with his series for so long and continuing at it at a pace he is comfortable with. I'e read that even if he does die tomorrow he has already set the ground work for how the whole thing will end so people can relax something will come out to tie up all those lose ends.