Is it normal my best friend is always so miserable?

He's probably depressed and if you feel so down being around him, stop being around him then or stop being a shitty friend and talk to him.

Take him out dirt bike riding or something

TBH my best friend is like this too and there's some times where I'm actually mad at her, like I understand things are bad and whatnot but don't cancel five times within the span of a week.

Whenever this happens, because yeah, it gets me down too and I hear you, I just don't initiate conversation with her. Like, I'll send her some memes on IG and stuff but I won't go out of my way to make plans or anything. Its not worth it for you to go super out of your way, you can bring a horse to water style. She always comes back around, even if its after a month or so. I let her have her space to rest and recover however she sees fit, and it works for us :)

You don’t have to be around them to be friends with them.

Dont waste your time with losers.

Throw a poo at him and say "see, things can always get worse"! That should make him feel better about his normal state.

Maybe he's suffering from depression?