I don't think (s)he has a 15 h/w job, they just work 15 hours per week. When you work for yourself you can do this. It takes some time to figure out what works but 15 h/w at $100/hr is ~$6,000/month.
If you do good work and find clients that are willing to work on retainer, it's not that hard. Lots of companies are willing to pay a decent amount to keep someone around that is responsible and does good work.
Also, if you work for yourself, you have to check the salary mentality at the door. You have to start with, "what do i need to make per month to live comfortably" instead of, "Developers usually make $100k a year, so I need to make that".
Found a small agency that is oriented towards remote and flexible work. Offered to join w/ the expectation of 15/week. Started as a contractor for them, then switched to hourly employee once it was clear we were a good fit.
At my prior job, I was offered full time. I responded by proposing 35/wk, with a proportional salary reduction. At the next compensation/review meeting, I successfully asked to reduce to 32/wk (same pay).
Honestly, I have no idea. However, that is the kind of person he would need to be to get a 3 hour a day programming job. Or he is full of shit and talking out of his ass but that would be uncivil so I better not say that.
Or he's a programmer with a respectable hourly rate (100+) and only works a few days a week remotely who lives in a cheap area. Any decent programmer can attain this.
If you do good work and find clients that are willing to work on retainer, it's not that hard. Lots of companies are willing to pay a decent amount to keep someone around that is responsible and does good work.
Also, if you work for yourself, you have to check the salary mentality at the door. You have to start with, "what do i need to make per month to live comfortably" instead of, "Developers usually make $100k a year, so I need to make that".