It starts in January, just after Christmas. It only takes Tony five minutes with F.R.I.D.A.Y. to confirm what it is. In the end, he’s not even surprised.
He hides it for months. He has to. It is a well known fact that an engineer is only as good as his hands. Tony Stark is just that: a pair of hands that create. If those hands fail, his identity, his purpose, is lost.
At first, it’s not hard to conceal. He doesn’t see many people besides Pepper, nowadays. Happy is far too busy running SI’s security branch to take much notice of the little things and Rhodey spends more time in D.C. than anywhere else. Pepper does ask about it, once, but Tony bullshits an excuse. He doesn’t know if she really believes it, but she doesn’t ask again.
There’s only one other person who would notice, and the kid’s at MIT most of the year. In all honestly, Tony misses Peter like hell. Cambridge isn’t far, especially when you have a private jet and a suit that can achieve supersonic flight, but the billionaire has been trying to keep his distance. The kid needs time and space to find who he is outside of Tony Stark and outside of Spider-Man. Tony will be damned if he fucks that up.
But now it’s summer, and Peter is home.
He’d missed the hell out of this kid. They aren’t even talking at the moment. Peter is engrossed in a project in the lab’s corner while his mentor tinkers with Dum-E’s wiring, but there is a contentment inside Tony’s chest that makes the silence the most comfortable sound in the world.
And then his hands start shaking.
He tries to power through, like he always does, but it only takes him five minutes to lose his grip on the screwdriver and send the tool clattering across the floor.
The string of curses slips out before he can even think them through.
“Mister Stark? Is everything okay?”
Peter still calls him Mister Stark. Even after all this time. Even though the young man is very aware of his future inheritance. Even after fighting through a war side by side. This damn kid has never stopped looking at his mentor like the man can lift mountains.
And now he can’t even rewire a damn robot.
“It’s fine, Peter.”
But the kid is peeking over his shoulder now, looking at his shaking hands with a shadow of fear on his face.
“What’s wrong?” Peter’s eyes are flashing between Tony’s hands and his face. “Mister Stark? Is-is it your anxiety? Do you need something? What-what can I do?”
Peter rarely stutters, anymore. Tony hates that he’s the reason he’s doing it now.
“It’s fine, Peter.”
“You keep saying that, but I can tell it’s not true.”
“It’s fine, Peter.”
“Stop saying that!”
Tony’s hands are shaking even harder now. He can’t tell if the tremor is just naturally progressing or if his stress is exacerbating it.
“I’m saying it because it’s nothing for you to worry about, kiddo. I’ve got in under control.”
“You don’t always have to do this, you know.”
“Try to handle everything on your own. You don’t have to. I want to help.”
Peter’s eyes are so genuine. He’d never lost that glimmer of innocence, even after Thanos. Something akin to hope kindles inside Tony whenever he sees it. Whenever he remembers that the kid was beaten, but never broken.
“I know you do, kid. But you don’t have to worry about me.”
“But I do worry about you, Mister Stark.” Peter is pulling him away from the wires with gentle hands. “And when you shut me out, I just worry more. Please tell me what’s wrong.”
Tony sighed, gripping the couch with white knuckles. Even then, he could still feel the tremor.
“It’s just a little shakiness, Peter. I’m not sick.”
“But…” Peter’s hands ghost over Tony’s. His face has taken on that soft, introspective quality that Tony has come to associate with the kid’s moments of deep thought. “But why are you shaking?”
“Don’t be an alcoholic, kid. Old age ain’t pretty either way, but it sure doesn’t help.”
Peter’s a genius, so it doesn’t surprise Tony that he connects the dots immediately. “Nerve damage.”
“Is it…” Peter’s voice is hesitant. “Is it permanent?”
“I don’t know, kid. Is nerve damage usually repairable?” Tony didn’t mean to be curt, but his frustration was leaking out. “What use is a genius level IQ if you’re not going to use it, Peter? Don’t act stupid. It doesn’t suit you.”
Peter blinks. He’s seen Tony be harsh, but it isn’t usually directed at him. He’s seen so much of Tony’s rarer gentle side that the prodigy often forgets that his mentor is a notoriously bitter personality. “I-I’m sorry, Tony.”
Every ounce of anger rushes out of the older man at once. “Don’t apologize, Peter. I’m not angry with you.”
“Who are you angry with, then?”
These are the moments that make Tony’s head spin. The moments he remembers that while Peter isn’t a teenager anymore, he is still so painfully naive.
“I’m pissed at myself, buddy.”
Peter pulls Tony’s hands away from the couch. The billionaire looks down. The kid’s hands are soft and young and steady. They have decades of innovation just waiting for them. A lifetime ahead, glowing like a promise. But for Tony, there is only a clock running low on time. Numbered days. For a moment, he wants to hate Peter for it.
“What use is an engineer with shaky hands, Peter?”
“But you’re not only an engineer, right?” The kid gives him one of those special smiles that make the older man’s heart fill with all sorts of obnoxiously gooey emotions. “You’re a lot of other things. More important things.”
“Uh, you’re Iron Man.” Peter says it like there isn’t anything else in the world that could be more important or impressive. It occurs to Tony that to the kid, that’s probably true. “You’re a genius. You’re a billionaire, and the owner of a company, and an icon. And you’re a husband. And a, uh, and a…” Peter blushes, and Tony just barely catches his final words, “and you’re kind of like a dad, too.”
Tony doesn’t need to ask to who.
“You’re a really good kid, Peter.”
Peter looks at Tony like his mentor has just handed him a bushel of stars rather than a half-assed complement, and Tony decides that maybe he is more than a pair of hands, after all.