My uncle wants to be a professional wrestler

I don't think he can still make it. You see, he's too old if he's just starting now. What I know is you have to have your body conditioned since you were younger, have started his workouts in his early years, just like Manny Pacquiao, I guess, he started as boxer when he was 17 and continuously doing the workouts and preparation until now, that's why his body is well prepared for his fights. At 40, the bones are not that strong if you haven't taken care of it during your early years, but he can do his workouts but I don't think he can compete professionally at his age now.

It is possible, but make sure that your uncle has the guts to be a professional wrestler. They say, no guts no glory.