...from memphis beat s02e07

-Okay, go ahead. You can talk. It's just us.
Brad spoke to you a couple times a week for the last two months.
We know he meant something to you.

We just talked about football That's all.

-We know that isn't true.

-I don't think your life gets easier if we haul you to the precinct, does it?

-Look, man, I live with my aunt.
She's sick.
Brad would stop by and give us money for medicine.

-That was a solid thing for Brad to do.

-Man, we just talked about football.
Next thing I know,he'd gone down to the BGD lieutenant
I used to sling for and got me out, free and clear.

what does it mean solid thing?
It is an informal way of stating that something is "good", "very good", or "great."