Maybe it's my crappy English, so I'll try again.
When you're calculating his renders per day
here, you're treating weekends as regular work days. When some people here say he's been taking two weeks off between updates, they're treating weekends as workdays (as if they assume the dev has to work on weekends). You're not new here, so I'm pretty sure you've seen this - when he didn't update his progress report for 1 day last week - some people here started with "is not moving today", basically expecting him to work 31 days a month. If you've been aware this month, he had updated his progress report almost each and every day - implying he had been working at weekends.
I know very well what you mean by "vocation days", but he doesn't have a proper employer and his vocations aren't regulated. So please tell me what's the difference between:
1. working 5 days a week + taking 20 days vocation (resulting with 124 days a year in which a person isn't doing work), and
2. working 7 days a week + taking 124 days vocation.
In terms of work days per year those 2 very different scenarios are exactly the same.
It's perfectly fine to expect him to work 7 days a week/30.5 days a month, but then you must allow him the same "days off of work" as you and most people in the western world have - which is 120-124...