Yes, he's paying an additional $2100 a month (which will rise over time) to cover all food (includes alcohol), daily maid service, utilities/internet, sea transportation, and at least a baseline level of included entertainment. Probably sounds like a lot to you and me, but if he always eats out or gets takeout all the time anyway, it probably seems like a wash to him.
It's marketed as a "luxury" cruise ship that caters to the wealthy. These tend to be much smaller than your typical gargantuan carnival cruise ship. It looks to me that they are also trying to suck in more modest income people with the cruise equivalent of timeshares.
Recreational ports all around Europe . . . there are worse ways to pass the days.
I predict he will tire of it, or he'll meet a life partner during his travels who tires of it. But then perhaps he can bail somehow? Or maybe he'll just become a salty dog?