I Have A Neighbor That I Have Lived Beside For

I have a neighbor that I have lived beside for the past 5 years now, who constantly whistles all day long. He even whistles while having conversations with family and friends and actually gets louder during his conversations. He also repeats everything he says at least 3-4 times and whistles maniacally when not speaking! He is in his mid 70's and I have noticed that he seems to be getting much worse this past year. Is this behavior some type of ADHD syndrome?