Nicely done

Lol, thanks for the reminder! Nicely done :)

Congratulations on your first Voltron fic! Welcome to the fandom!

This story is excellent! Both the writing and the characterization are well done.

I have one thought: if Keith has come to Shiro like this before, then Shiro would probably think of it as a possible reason for Keith bothering him, and not be so reluctant and resentful about letting him in. Unless Keith has also come in the middle of the night for other reasons; if that's the case, you might want to mention it, but it would still make sense for Shiro to think it might be some kind of emergency.

I didn't see any typos, but there were some points of grammar and syntax that I thought could be improved. (I'm sorry if I do a bad job explaining them.)
~ "suggested" and "most definitely" are very different in their levels of strength. One or the other would work, or you could change "suggested" to something stronger like "indicated".
~ The placement of "It was times like these" and "often" seems a little odd. One or the other would work, but looking at the context I think removing the word "often" would make the most sense, since "times like these" refers to times when Keith directs his anger toward Shiro, causing him to wonder how other people see Keith.
~ I think some tenses or verbs need to change in the line about Keith not wanting pity. "he'd learned by now" and "would" don't really work together because they're different tenses.
~ "there would be no way" should be "there was no way," since it is then followed by "they'd be able."

The explanatory note at the end isn't necessary. Those intentions (angst, sadness, irony) come through clearly in the story, so we readers can deduce them just from reading, without having them explained to us.

Sorry if this sounds like a lot of criticism. Overall I really like this story! I'm only being this nit-picky because it's already very good; I can tell you aim for high quality, so I hope this helps with that. :)

oUCH NOW IM SAD but in a good way because this is my favorite thing and also you know I’m a sucker for the foreshadowing stuff and I sorta laughed out loud at the “I don’t wanna come back and find you’re living in the desert bc you couldn’t handle being angry again” and I’m in the car and my dad is looking at me weird for laughing,, my point is I love this and please keep writing fics because you’re a role model when it comes to writing OKAY THATS ALL THANKS FOR THE BROGANES CONTENT (also yeah it’s me Isn’t my username so creative and different from anything I’ve ever used before hmm)

Awwww! I love me some brother fluff and this was so perfect and sweet. I love how Shiro started off disappointed (fighting again?) but when he realizes the reason that started it he stops with the lecturing (mostly :p) Poor Keith; he just takes everything to heart, even an offhand comment from a drunk upper classman. Sweetheart needs a hug, but since he's not really up for that at least he's got Shiro looking out for him... until, well, all that goes to hell in a handbasket.
Thanks for this lovely little gem!