As someone else said, maintaining boundaries is one of the ways he shows he cares. That's something that's really important to me, especially because of some past stuff with other people in my life including previous Ts, and blurring boundaries or treating me like I'm "special" would not be doing me any favors.

He tells me he cares and that he likes me.
I think a biggest thing is just hearing fondness in his voice sometimes.
There have been a few times a joke has made him laugh so much that it took him a minute to compose himself while apologizing for laughing that much. And when he laughs it seems genuine.
Sometimes he grins like an idiot when I tell him about something he'll see as progress or something positive. And I roll my eyes at him and tell him to stop looking so happy about it and he doesn't.
I catch him smiling sometimes when he doesn't know I'm looking.