You think Drake was happy when the Toronto Raptors won the NBA title?
His dad was even HAPPIER -- because Dennis Graham had $100,000 riding on the Raps ... AND WON!!!
"I am the happiest guy in the world," Dennis told us in Hollywood with 2 ladies on his arm .
"I bet $100,000 on the game and I won $300,000!!!"
You see this? Drake's dad is RICH!!! (Okay, *more rich). PIMP HATS AND CHAINS FOR EVERYBODY!!!
There's more ... Dennis also has some advice for the Raptors when it comes to visiting Donald Trump -- DON'T.