How should i help my very troubled friend? is he insane?

He dresses like his Guild Wars character and runs around the neighbourhood and starts throwing boomerangs and rotten meat at people who do bad stuff like vandalize houses and steal. He calls himself the A.D.D. Man. he says he has a arch nemesis whose he's always battling named DR. Vandalism and they're always duking it out with boomerangs and heavy objects and stuff. he's 19 years old and i'm concerned about him, what should i do? should i just ignore it?