Capitano's Return Based on Genshin's Only Precedent
Sandrone is the only character who was explicitly shown to die in the story and then come back to life.
That means we finally have a precedent for character resurrections in Genshin. If Capitano is going to return someday, looking at what happened before Sandrone's revival might help us predict the timing.
So the real question is: Were there any signs before Sandrone came back?
My answer is: Not really.
From Version 6.4 to 6.6, there was essentially no new information about Sandrone at all. Most of the details that were actually connected to her revival weren't revealed until Version 6.7.
If this is the storytelling pattern HoYoverse follows, then it's entirely possible that Capitano could also return without any obvious buildup or foreshadowing.
A lot of people say, "Capitano has been appearing and getting mentioned more often lately, so he must be coming back soon." But as far as Genshin is concerned, there has never been a character whose resurrection was preceded by a noticeable increase in appearances or mentions.
At the end of the day, that's just fan speculation. I think it's more reliable to base our expectations on the storytelling pattern that Genshin has actually used rather than assumptions made by the community.
Could Capitano's recent appearances be foreshadowing? Absolutely. But they could just as easily be fan service.
What we can say is that, just like Sandrone, he could return completely out of the blue.
So even if we go through several future versions without any new information about him, don't lose hope.
Thanks for reading.