She bends over instinctively (not as far as she had, how long has it been since she saw him?) when he runs to her, so he can put his arms around her neck, and the immediate rush of relief and joy and love all but drives her to her to her knees, pulling him with her and into a proper embrace.

"It's all right," she murmurs, holding him tightly, kissing the top of his head. "It's okay, I'm here. Oh, Kubo."

He's older. He doesn't fit into her arms quite the same (though it's not an alien feeling at all, of course). She doesn't even care, right now.

It means he survived.