It is canon that at some point, while Hiccup was still in a coma, Gobber went through his room and workshop to find the schematics for Toothless's tail. I cannot imagine that Stoick did not join him.
What must it have felt like, seeing all of Hiccup's drawings and models of Toothless? There is so much to unpack about what they would have thought.
They must have been struck by how little Hiccup hid his things (a canon detail!), because Hiccup knew they didn't care enough to notice. He left drawings of Toothless out ON HIS DESK and never worried about it.
Can you imagine? Your child loves something so deeply that it has become intrinsic to who they are, and you know they knew you would hate that thing if you found out, and you realize that they felt like they didn't even really need to hide it because you never looked at them enough to notice. And they were right.
And, also, Stoick and Gobber must have appreciated for the first time how incredible Hiccup's inventions are. Gobber had to break down the tail schematics to recreate it, which meant he had to fully confront how the tail control mechanism was light-years beyond any other piece of technology on the island.
They would have found, too, Hiccup's first few attempts at the tail. They would have been confronted with the fact that when given the space to test things, to try things and iron out the flaws, Hiccup is a genius. All those old inventions that almost worked but malfunctioned in some way? Yeah, if the village hadn't stopped Hiccup, if they had let him take notes and try again, those inventions probably would have worked.
Can you imagine what they felt, realizing how badly they had stifled and mistreated Hiccup? Realizing that if they had given him space to be himself, he would have been creating miracles his entire life?
ALSO, Stoick and Gobber must have truly understood for the first time how deeply Hiccup cared for Toothless. Hiccup made technical drawings for the tailfin, yes. But he also canonically drew a lot of art of Toothless just. Being Toothless. In the Live Action he even made a wooden carving with articulated wings! It is so evident from his space how much he loved Toothless. What do you think Stoick felt, seeing that, knowing how he himself treated Toothless after the arena fight?
There is just so much that comes from that small detail of Gobber making a new tailfin, and I desperately want, like, a novella from Stoick and Gobber's POV of that time period.
