they didn't write "you have time", which IS a statement, they wrote "you have time?" which IS a question. You do not need a "do" or an "if" in order to ask a question. For example:
Janice: "Man, Bob, you have been crazy busy today, I've barely seen you at all! when would you like to have the meeting?"
Bob: "Yeah, it's been a crazy day. How about we meet now?"
Janice: "you have time?"
Bob: "Not much, but we can have a quick meeting"