If they are freely joining his games, then he can play forever. However, if he is luring new players to join, then there could be an issue.
"Newbie Farming" is the technique of setting up as many games as possible (either by starting or joining them) with New Recruits to gain easy points by taking advantage of difficult game options and the fact the New Recruits are more likely to deadbeat. Some players have been farming extensively - even sending hundreds of PMs to the latest members to get them into their games.
I'm not sure if this map and settings would be considered difficult.