Oh, dear, me, @Tits, he is searching for his bat.
If he were shining his flashlight in one steady spot, pointed downward, it would be obvious that he is engaged in some sort of ritual. But if he is shining it frantically all over the place, you know that he is trying to follow the movements of something airborne, and only bats fly like that.
He must be the very person I heard about on NPR last week, the one they call the Batman (cute, huh?). He rehabilitates wayward bats, especially those that are delusional, and retrains them so they can go back and become productive members of bat society. Models proper bat behavior for them and helps them regain their taste for insects when they’ve been too long in the city. (Some of them get into junk food, and it’s really bad for them, especially for their memory.) From time to time he has to deal with a runaway. If you could hear him you would know he is also sounding a special batcall whistle at their sonar frequency. Sometimes the older ones especially get disoriented and he has to call them in and adjust their meds.
Don’t call the cops. But do watch to see if he is wearing any sort of special costume. You’ll know it’s this guy for sure if his clothes flap at all.