A reset won't do it, he needs to advertise. Offer new players up until level 15-20~ more xp gain or something, something to catch peoples attention. Make a tutorial island maybe that shows you all you can do with the iron ores and everything. Show each rock and how each one works, and what ores give what % of breaking or succeeding on things. Stuff like that. Advertise a thread to re-open the server (just shut down the server and make thread, put it back online after) and it may have more players. Like, close it for a week, make thread, after a week, put it online and let the new people come online with the new and improved things. Thats just a few things to start, since I read this quick ^^