George R.R. Martin is somewhat in the dark about how Game of Thrones ends

Entertainment Weekly

“I haven’t read the (final-season) scripts and haven’t been able to visit the set because I’ve been working on (The Winds of Winter)," Martin tells EW. “I know some of the things. But there’s a lot of minor-character (arcs) they’ll be coming up with on their own. And, of course, they passed me several years ago. There may be important discrepancies.” Martin also says he has "mixed feelings" about the end of the series, adding: “It’s been an incredible ride. And almost all of it has been great. Obviously, I wished I finished these books sooner so the show hadn’t gotten ahead of me. I never anticipated that.”