Steve knew what Bucky had gone through, he'd been there to see it unfold and he'd protected his friend fiercely against every threat because he knew who he really was. So Steve got it quite quickly really, when the furious looking Pokemon rushed him and Bucky's explanation hot on its heals. With Steve showing no fear his own Pokemon picked up on that and while he stayed behind his legs for a moment he slowly emerged bit by bit. "Be gentle with our new friend," Steve warned his Pokemon as he got closer. They were just two dogs, them and the Pokemon really, trying to make their way.
He'd have kept it casual, taken off on his way if he'd felt like Bucky didn't want him there. But he'd come out a little and he was lingering and Steve didn't actually want to go. Steve missed so much of their youth, sure there were parts he didn't like to think of, how poor they'd been and Steve's health had left a lot to be desired. But things had been so simple, simple and good and Steve missed that, he missed Bucky. But they'd both changed since then, changed and grown.
When Bucky had arrived and stayed back from him it had been the start of something different. Steve hadn't expected him, he'd thought he was dead and that was before people had started showing up, people he knew and knew to be gone. He'd been living with Tony and Bucky had been confused, they'd all kind of been confused. But it had been the start of their 'breakup' Steve realized now looking back.
They could have left it at hey, commented on the weather, kept the talk to Pokemon. But Bucky asked how he was and Steve knew that meant he wanted to know. "It's been a lot," Steve said quietly. What with Tony being dead and married in the future, with Natasha being so upset with him, then his own pain on top of it all, a lot seemed the only accurate description. "But there's been a lot of good with the bad. Some great, too." Steve straightened up, content the Pokemon seemed okay together.