Seniors

This teen could be the next one to use his guns.
Or maybe he'll just keep terrorizing the neighbors knowing they worry that he'll use his guns.

Some will say, "Make friends with him. Be nice." And yeah, sometimes that can turn a "bad kid" towards the right path. Many adults can look back and remember a kind adult who reached out and made a difference.
Then again, I did that with a neighbor boy, and the next thing I knew, he was stealing from me.

(He still lives on my street, btw, and actually started a painting business with his brother, and seems to be a solid citizen, though he does block the street with his work trucks. I don't begrudge that though! At least he got better, not worse.)

Boys who have guns when they're still in their teens, and enjoy harassing people, well, I wouldn't trust that kindness will keep them calm.

The family won't do anything. At some point, maybe the cops will, but maybe it will be too late.
Sorry you're having to go through this! Can you minimize your contact with them? Let other neighbors take the lead?