Until that point, part of Gar's problem had been that he couldn't quite relate. He's lost his parents when he was five; he barely remembered their faces. But now he realized that she was only seventeen (or three, or something) and so she got to meet her family only when she was practically done growing. She'd had to construct a family out of bits and pieces.
That was definitely something Gar could identify with.
"Look, I know I haven't been... the most supportive person lately. Like we said. We both kind of suck. But as far as I'm concerned, you're my family." Gar gave her a small sort of smile. "It's not the best situation. One or both of us might disappear. But as long as we're here together, you've got me."