Here's a thought: What if Keith himself disappears/ goes missing at some point like Shiro and we get to see how Shiro would react to the team telling HIM to move on? Keith very much suffers in silence until his emotions can't be restrained, bc he sees his emotions as a shameful part of himself, but Shiro? I can see Shiro not being scared to call the others out on any bull, and he'd know just how scared Keith is of being left behind and abandoned -like the others would be sad but accepting of.
oh I do think that’s completely possible. I think a big determining factor of how he reacts though is whether it would be our Shiro or Kuron. I think Shiro would be the one really advocating to rescue Keith though–like he did when Allura was captured. Though, it is possible that, if the search takes too long, the others might also come to the same conclusion of We’re sorry we lost him, but Voltron has to come first. As painful as that is. And yes, Keith is used to rejection, is used to being alone. And I’m sure Shiro knows enough about that to try and save him no matter what. How could he sacrifice Keith knowing it’ll make him believe that his most important person gave up on him?
Shiro has also been shown to be especially aggressive and protective when Shiro’s in danger. The very thought of Keith dying makes him furious, and he’ll fight anyone to keep this boy safe–alliance be damned. And we see time and again how he’ll lash out to defend Keith. Even when he does let Keith throw himself into danger, he’s right there to offer support (and clearly looks pained when he reluctantly agrees to it)
With Kuron things might be a bit trickier because we don’t know how much influence the galra have over him at this point. But still, I’d like to think he’d still feel something for Keith and try and chase after him. After all, Keith was the only one he trusted at his bedside. And it was Keith who promised to save him “as many times as it takes.” That really meant something to him. If Kuron is in fact a clone, then this is one of his first significant relationships with another person. Seeing how much Keith cares about him–and how he cares about Keith in turn through Shiro’s memories–I think he’d feel compelled to look after Keith as well