Mining Profitability
Mining Bitcoin at 40 MH/s is not profitable. 

Unless you get free electricity and consider 4 cents a year profit, there is no point mining Bitcoin with that hash rate.

Does your friend's dad have $10 in Bitcoin from mining with that hash rate? Simply put, no. Your friend's dad could have, however, been mining a different cryptocurrency without knowing. 40 MH/s mining Ethereum produces $3 a day.