Edit: Just discovered that the profit is $835 USD per month. It seems this isn't enough.
1890 ads / month - (55 coin leaderboard per months + 1000 servers per month)
1890 - 1055 = 835
That is some interesting math. Not sure where you came up with $55 in coin leaderboards per month when there are ~$280 given out as prizes every 3 weeks. That works out to $370 a month.
Even if your ad revenue figures are correct we are still looking at ~$500 a month. Assuming he works on this near full time and that equates to about $3.13 an hour.