Disclaimer: Final Fantasy VII is the property of Square-Enix. No profit is sought from this work.
Tifa doesn't need him. She doesn't need anyone. She's a tough lady. She can kick her way through a brick wall if she has to and she has already, on several different occasions. She doesn't need him taking up space, messing up drink orders or breaking the dishes. She doesn't need him tracking up the floor or leaving engine grease on the doorknobs. She doesn't need him leaving the toilet seat up and forgetting to put the cap back on the toothpaste.
He's not the most helpful or useful person to keep around the house. He can't tell a squash from a marrow and fixing busted plumbing isn't his strong point. He does all right with faulty wiring, but only because mild electric shock doesn't bother him.
The kids run rings around him, exploiting the soft spot for children that he didn't even know he had. And when they get in trouble because of something he let them do, he's the one Tifa pins to the wall with an angry glare. Well, no, really, how was he supposed to know Tifa had already told the munchkins 'no'? No, he'd never thought to check with her first. He didn't realize that kids would play one parent-figure off another like that. He's never had two parents at any point in his life that he can remember.
He'll go off to his room and think about what he's done anytime being off on a delivery isn't an option. It's the best he can do for her sometimes, staying out of the way. She'll call him down for dinner and he'll spend as much time as Denzel does just poking at the vegetables he can't quite name, spiced with herbs he didn't know existed till recently. Tifa might scold him for setting a bad example and he'll shovel it into his mouth. It's good food, it really is, though he can't help but wonder what Tifa gets out of feeding him.
He thinks about it a lot when he's off on his bike, kicking up dust with no one to worry about or no one to worry over him. Tifa doesn't need him. She has enough to handle as it is without trying to give him a stable place. She doesn't really need another kid to handle, especially not one as overgrown as he is.
And he is a kid. He shouldn't be, not really, he knows, not at his age, but he is. Despite all that's happened and all he's done, sometimes he still can't quite accept that he went to sleep at sixteen and woke up five years older. Those years are there for him to claim if he wants to, but he knows what's there and knows how bad it is and he'd rather flounder around and be forever five years younger than his age than hold those five years any closer than they are. It's better for him to finally leave that burden behind. Tifa didn't like the way he dragged it around with him all the time anyway.
He used to run away from the home she had made for them, but his running days are done. His problems aren't half as huge as he used to think they were and it's not fair to her for him to just up and leave, even if he is pretty useless indoors. No matter how far business takes him, he'll always go back.
And Tifa smiles when she spots him walking through the doorway, always, even if he only went out for ten minutes to get the things on the shopping list she had given him herself. He has started smiling back now. He doesn't really understand what's happening, but he thinks it will work itself out. It will be all right. Tifa may not need him around but she wants him around and that makes all the difference.