Yet, he developed a fair bit of software for this free already. Sometimes people do things for the public good. Plus you know he's going to be hired somewhere else after this if he wants to, and if he owns the software he develops, he can make bank.

I know Tim personally, since he contributed for years to the SageMath software project while he was in high school here in Seattle. He is an extremely sincere person, who care intensely about things (like open source software), and has little interest or motivation related to money. The potential that he could have any impact that could improve the terrible police/people interactions even a little in Seattle is I'm sure all he cares about. I very much wish him the best.

Whether or not he cares about his bank balance doesn't change what fair compensation is. If you frame this as "you can donate $10 to your favorite cause, or $50", the rate might seem more meaningful.