Actually I think calling it 'financial independence' would head off a bunch of knee-jerk reactions and make it a lot easier to have a real discussion about.
If you're working for money you're not retired. There's even a whole spiel in the link above about how they tried to become property developers which failed when the market collapsed, which is actually a lot of work.
I'd buy semi-retired. Or he works part-time. But retired has a very specific meaning that he is ignoring. He just seems to be confusing 'I enjoy my new job' with 'I don't work' just because he didn't like working 9-5 as a programmer or whatever it was he did.