In the disclosure statement on a home sale, I wrote that the old roof "leaked (replaced) age 1 year old". The buyer is suing me in court for a leaking roof saying that I had misrepresented the state of the roof. Does he have a leg to stand on?

The buyer relied on your disclosure that the roof was replaced and 1-year-old. When you used the words and terms "replaced" and "age 1 year old" the buyer would have the understanding that the roof was replaced new and is a year old. You, as the seller, had a duty to the buyer to disclose the exact and complete details on where the roof leaked, what was done to fix the problem, methods and areas of repair or replacement, was the entire roof replaced or only certain sections, was the roof framing/system replaced or only the roof covering, was roof sheathing, flashing etc. replaced or just the roof covering, who did the work: homeowner/seller, handyman or licensed and/or professional experienced roofer, what are the terms of the warranty if any etc. You would have a defense only if you disclosed everything about the roof, i.e. specified exactly the locations of the leaks, that the roof was not a new roof, exactly what areas were replaced, how and by whom, the roof is sold in as-is condition and you give no warranties as to the condition. If you have this agreement in writing then you may be protected. It appears in this case that your disclosure was ambiguous and not full and complete. If the current leak is in the same area as the old leak, then it may be established that the corrective replacement was defective.