Wanting to analyze your question directly actually you could have made him interested in the business by giving him the money. Suppose you gave him money and he placed a bet on gambling and won but that is not the end because it made him greedy for gambling. Later he would save money and place a gambling bet and lose. Gambling is proven to be a game of luck so it doesn't always win. If you want lend him the money and ask him to repay it in daily wages. We don't all have the same financial position so we shouldn't call anyone to gamble.
It is better for us to stay away from lending money to anyone for gambling or getting interested in gambling. Because I have seen some of my friends who borrowed money and paid it back in the first instance but lost all money after some time when they lost gambling. He could not pay back the borrowed money when he left so we should refrain from lending money to anyone for gambling.