He’s only describing 22 days and 12 of those will just be a morning, two overnight. I’m sure you could manage that out of 365 days.
Being in full time employment, it isn't 365 days though, it is effectively just weekends (holidays are generally taken up with other activities), so you are only talking about roughly 100 days maximum when I can theoretically do rides of much more than an hour.
The "just a morning" (or more commonly an afternoon), yes I can do those (and do - a 35 mile ride normally takes me around 2.5 hours, and I've done 13 rides of 35 mile+ this year). But he was talking about having done 12 metric centuries - that will be 4-5 hours for me (I've done one, in company, and that took 4:15 for 68 miles). To me that is a bit more than "just a morning"
But overnight isn't going to happen at all. And to take 10 full weekend/holiday days on top of those 13 longish rides, again not going to happen if I want to stay married.
Part of which is because I have two other hobbies that take up a lot of summer weekend days, with Morris dancing and Sealed Knot. My wife is involved in the Sealed Knot, but not the Morris dancing, and there is no way she is ever going to be able to come cycling with me, even if she wanted to.
I certainly hope to manage a few more metric centuries next year, but it isn't going to get anywhere near 12 of them, nor 4 imperial centuries - though I would really like to do at least one.
In 2-3 years time I will probably be looking to start winding down towards retirement by going part time, and if I drop to 3 days a week, that will far more than double the number of available days I have to take longer rides, and then I may well be able to get up to those sorts of numbers.
There have been 193 days this year when I have been active on the bike. But only 13 of those over 35 miles.