Granny doesn't know, but she still remembers the first time her parents told her they had to leave. She was so young, but every now and then she can see flashes of their faces as they knelt in front of her, all smiles and kind blue eyes - her eyes. She remembers how cheerful her father was as he patted her head and told her to be good for Granny, and how her mother had smiled through watery eyes when she told her not to worry, they would return before she knew it.
That had been the first time she'd had to watch someone's back slowly shrink into the distance, out of her reach, and it had been the day Granny had told her that while it was okay to cry, she also had to be strong and stay confident that everything would turn out okay.
And so she had begun the waiting. Granny began to teach her how to work with automail, and she of course had taken to it like a true Rockbell. She would spend her days doodling automail designs and helping Granny with clients. She would rough-house with the Elric boys next door, even though every day she would huffily proclaim that she didn't want to play with "that stupid meanie Edward" anymore, and would earn looks of pride from Granny when Edward would complain that Winry had clocked him for teasing her again.
And every day, after telling Granny the story of her day in a single breath, she would take a deep breath, look up with large, hopeful blue eyes, and ask when her parents were coming home. She always got the same answer: "Soon."
It wasn't soon, but they did return - in boxes.
It is a day she will never forget, no matter how hard she tries. She remembers the way the soldiers who brought them seemed almost as sad as she was about the news; she remembers the way she began to wail in confusion and anger that they were wrong, her parents had said they would come home and that's what they would do; she remembers the way Granny's face seemed to break, its usual all-knowing smile shattered into anguish; she remembers the fear she had felt when she'd seen.
She remembers how quickly Granny had arranged her face into cool composure, invited the soldiers in for tea, hugged her close and reminded her to stay confident, that everything would be okay.
Winry has never told Granny that she remembers all of this, though. She never will. She knows now the importance of staying strong. She understands why Granny had composed herself so quickly, had refused to show her despair over losing her only son. She knows now that waiting can only have two results, and she has to be prepared to face them both when the time comes.