Honestly he should open a Patreon. There are loads of people that would subscribe to Sudo for $2/month or $5/month.
The problem is if I was going to do that with the open source projects I use, it is more like a penny a month * 1000 projects.
They are using github sponsors and have had some level of contributions.
wouldn't https://github.com/sponsors/sudo-project achieve the same thing in this case?