Nah. Very few pro strongmen weigh 400 lbs. It just so happens that the 3 top guys right now do. At the Arnold this year, 10 of the very best in the world were competing, and 2 of them weighed right at 300. Several more were sub-350.
The fact is that if he learns the sport, he could earn a pro card within a year, unless he happens to be just absolutely terrible at moving events. That remains to be seen.
As to what Wheels SHOULD do: whatever makes him happy is the real answer. And from interviews, it sounds like he wants to be great at strongman, powerlifting and bodybuilding. Competitively speaking, I see no reason for him to stay in powerlifting. The dude has already set world records. He’s essentially already hit the ceiling of that sport.
I don’t think he’s ever going to hold the highest PL total ever, I don’t think he’ll ever be Mr Olympia, and I don’t think he’ll ever win WSM. But, I do believe that he can be a world record holder in powerlifting below SHW, He could land himself in the top 5 at an Arnold or WSM, and he could step on the Olympia stage as an IFBB pro at some point. Just reaching that level puts him among the absolute most elite competitors in each sport, and that would be an accomplishment we’ve never seen before. It’s really baffling to see some of you guys taking the mindset of ‘well if he can’t win the Olympia, no point in competing in bodybuilding, he should just stick to youtube.’ I don’t understand that mentality.