Buy or develop your own time machine and go back to 2008 and mine BTC on the computer at your mothers house in the basement
If you want to become rich then you will need to work hard and only focus on working and working that is how you become successful.
People who are rich these days all worked hard and did not think about the money.
Yeah work hard can make him rich but first tell him that where he have to work hard, as work hard in a field like gambling is not going to make him rich, he should have to start a real investment or have to do a job etc.