Yeah I found out some info about people getting random spam followers out of the blue. Apparently there are these click farm/spam bot businesses which hide their fake profiles by liking/following all sorts of stuff. So it could be that poor Caleb was an innocent victim- just another reason for him to be sad
I watched a vid where it shows how it can be a real problem with Facebook likes because you can buy legitimate advertising from FB to increase your likes, but you'll end up getting hit by click farms trying to hide themeselves. That then drives down your engagement levels which means you don't get shown on your legitimate followers timelines. Basically Facebook is terrible and a scam.
Here's the vid for those interested
https://www.youtube.com/watch?v=oVfHeWTKjag