It's a subculture that is both hard to define but also obvious when you encounter it. I think he'd still recognize it, especially now that so much of the community has been pushed to be vocally anti fascist, which kinda brings it back around to its punk roots.

In the olden days it used to be defined by a specific music genre (and even today you have purists who complain about anything that isn't goth rock) but it has changed a lot over the decades. I'd loosely define the modern goth as a counterculture movement based around music, art, and a fascination with the morbid, heavily concentrated around major cities. The only real gatekeeping nowadays (from the adults at least) is to keep fascists and creeps the fuck away.

The scene is gonna change a lot depending on where you are. The two I personally know best are NYC's and Toronto's.