By Uchiha brother, I’m assuming the latest pair. Itachi and Sasuke. In all technicality we do have a scene like that for the elder brother in itachi’s story, Shisui’s death. However, we all know there is more than meets the eye with any member of the Uchiha clan, so here goes

Uchiha Headcanon: Losing a close friend

Itachi

Itachi Uchiha would automatically accept this death

While he’d be hesitant to show it, this death would affect him greatly, and yes he would cry.

But he wouldn’t full out sob, you see Itachi has faced death since he was just a child and knows it happens to everyone eventually.

He would be the kind to indulge in sweets during times of sadness, moreso than he normally does (I mean c’mon, he amost awoke his sharingan when Izumi wasn’t going to share Dango with him)

Itachi wouldn’t find anyone else trustworthy to invest his emotions in so he would stay quiet

From the outside Itachi would look stoic and like the death never happened, However behind closed doors, He is a mess.

Sasuke

Unlike his older brother, Sasuke wasn’t exposed to death too much as a child (aside from the massacre)

Because of this, He’d have a hard time accepting this death

When he did come to terms, it would most likely be a funeral where he ends up having a full on breakdown

Of course he’ll deny it ever happened anytime someone brings it up

Like his brother, Sasuke would indulge in sweets. Even if he does hate sweets.

That would be the big hint that it does bother him

Sasuke would genuinely believe his friend betrayed him by dying, and thus hold a grudge against them for quite a while before realizing it does him no good.