As one very smart person used to say, the most profitable strategy in gambling is not to gamble at all...
That will be great advice for him, so he doesn't have to lose his money hahaha
I don't know how much big of percentage for use strategy for dice game since I don't use any strategy. But I guess the price will vary from one strategy to another strategy. But perhaps, there is a free strategy he can use to test his luck, but for me, I don't think there is a good strategy for a dice game that will work and help you to win the dice game.
I think the only strategy you can try is making limitations for the money you want to use in dice game so you don't use big money to bets and the best is, you can save the rest of your money