For me it would depend on the definition of, "Bro". I have some blood relatives that I wouldn't trust. And I have some acquaintances that I would trust with my life.
I don't let many know that I have any extra guns or supplies. People talk. I can't stand the usual statement, "Well if thing ever got to the point where SHTF, I'll just come to your house." So imagine if these same people told others where to go if things ever got bad. You're house could easily become a prime target. These people would most likely not be welcome at my house, much less be given weapons. But trusted friends/relatives who may have lost their gear due to natural disasters. Or because of a natural/man made disaster are not able to get back to their home. These people are those who I think of when reading this topic.
I am against the cheap quality AR's only because if the need exists to had out a Bro gun, then things are bad enough that the gun needs to be dependable. The Bro may be using your handout to protect you or your family.
I have a few extra Colt 6920's laying around that I bought in 2014-2015 with the expectation of Hillary winning the election. When I bought them, I had no intent of flipping them. I wanted to put something back for kids and step-kids. Or at least that's what I told myself as I was buying new guns. To be honest, I like buying new guns...
But now the election is over and I'm stuck with these Colt 6920's as the market is so soft. I refuse to sell them for what I would have to sell a used 6920 for (even though one is unfired and the rest only have one 30 rd mag through the gun).
I don't really have a use for a 16" carbine with a fixed front sight either personally or professionally. All my work and personal guns have FF barrels, ect. If I could sell them at a reasonable price, I would. But with the current market...
The recent round of hurricanes have made me think of the "Bro Gun" concept. My "extra" Colt 6920's have MagPul MOE SL furniture on them, and a sling. A red dot optic would be preferable, but I don't know that I want to throw more money into the concept. I did install a Mag Pul cantilever picatinny rail to each so a light could be added.
I can easily set aside 4-5 magazines per carbine along with ammunition and a basic cleaning kit and a means to carry the extra magazines.
Even without an optic, I feel that a basic 6920 with iron sights would still be an effective gun. Better than a sharp stick.
I have enough S&W M&P gen 1 and Glock 19/17 gen 3 9mm pistols sitting around that I could pair a 9mm with each carbine.