"A Song of Ice and Fire" has a legion of fans spread all around the world but some are class apart. Brynden B Fish is one such name. He has contributed a huge amount of content related to the book and is a well-known name on Reddit.
He also owns a blog that goes by the name of "War and Politics of Ice and Fire." Recently, in an interview with The Verge, the prolific blogger and theorist revealed a lot about Martin's work, his favorite theories and the future of the HBO series. He disclosed that he started watching the series mid-season in May 2011 and took to reading the books, only after the second season. When he was finished with the five volumes, he was mighty impressed with Martin and felt that the author had left open many things in the book, which prompted him to start writing.
Talking about his much-admired "Battle of Ice" theory, he said that he wrote about it picking on hints George had left in the book and firmly believes that Stannis would defeat the Freys and the Boltons if the book opens. He feels the show just snatched Stannis' role and blended it with Jon Snow as a lot of the things that Jon did from Season 5 to season 6 were actually what Stannis did in the books.
Talking about the R+L=J theory, he said that he had no idea about it while reading and watching the earlier seasons. He thought Jon's parentage was a mystery and would be revealed later on. However, he also has a very queer theory of his own about Jon which says that Varys is a descendant of the Targaryens and is working on a secret mission to bring the Dragon blood back to Westeros.
As for Dany progressing into the mad queen mold, he said that it is possible but if it happens it would look too clichéd. Martin has indicated at her violent streak but he hopes it does not materialize. He is also in favor of giving the author enough time for "Winds of Winter" as the complexity and politics that readers love so much in his work, needs time for creation.
The following video talks about R+L=J theory: