I can give you a few headcanons if you would like! Enjoy!
2p North American Bros:
-Allen and Matt are actually very close, their Snapchat streak is impossibly high…even though most of the pictures are completely black and just say “U ded bro?” and “Not yet.”
–Matt always complains about taking care of Allen when the idiot gets himself sick or injured…but secretly he wouldn’t trust anyone else with taking care of Allen.
-Allen always gifts Matt new woodworking tools or sends him sneak pictures of designs he sees when he is out. While Matt usually just sends Allen memes he stumbles across, though Allen never says anything if the meme is long dead…he still appreciates it.
-Allen occasionally suffers from nightmares having to do with Oliver, but Matt is the only one to know…and the only one who can truly reassure Allen that he is safe and sound.
-Matt sometimes goes through deep depressive waves that make it hard for him to even get out of bed, but Allen is always the one to drag him outside and make him feel better…even if he does get punched a few times.
-No matter what, these two will always defend the other if there is a clear threat. They are ride or die for each other, even if they fight from time to time.