honestly the 4th book is utter shit. its mainly brienne in it. no daenerys, no tyrion, barely any jon snow. the only thing entertaining was aryas perspectives. the 4th and 5th book occur at the same time, theyre like half books. he said he wanted to tell all the story for half the characters, rather than half the story for all the characters with the 4th and 5th, so the 4th and 5th are basically just one massive massive book. the 5th book made up for them both i guess, but the 6th definitely isnt going to be done by the time hbo catches up. especially because i doubt hbo will take his bullshit 'rather tell half for all characters' bullshit and they'll tell the 4th and 5th concurrently, so hes got two, maybe 3 years max to finish his 6th before hbo catches up... i suspect he'll only have about 700 finished pages by then, and hbo will have to start making shit up. he'll be writing down hbo's episode summaries lol
a dance with dragons took him like 6 years, and the 6th is supposed to be twice as long, same with the final 7th book. he'll probably pull a robert jordan and die before its finished. if he didnt spend half of his 10,000 total pages describing what people ate, how they traveled, and telling the entire histories of hundreds of minor houses and characters going back a hundred generations and describing sexual acts with teen girls in pornographic detail we might get the 7th in the next 10 years