Ignore him. Everyone has that one neighbor that is just a little out there.
I have one who lives in my neighborhood who has OCD, which is fine, he keeps his yard really clean and everything, but the SECOND something is wrong with someone elses yard (maybe went a few days over on mowing their lawn, or didn't trim some trees for a bit) he calls the homeowners association and complains about it and then they get letter threatening to fine them if they don't do it.
You can't fix other people, so when in doubt, ignore them 
