Not unbelievable, there are amateurs who take twice that and still do not become Pro. What I find useless is two kinds of tren together. Parabolan is a very slow acting tren, slower than Tren E, so stacking the two, despite being tren blends around, I don't see the benefit. At his level, with sponsorships and guest posing he probably can afford to run something more effective for a Classic Physique competitor, like Primobolan, NPP, HGH and a mild test dose. Classic Physique is a re-enactment of 70-80'S era body building, so between stage weight and off season weight you shouldn't jump more than say 40 pounds. They stay very lean all year round, not breaking into 40-50 pounds difference like superheavyweights competitors, who also need a lot more food to build and cut.
Also that seem a pre-contest stack, and I believe Primo and or Masteron would be included in that too. He can afford them and their are very cosmetic but also effective in a low body fat situation, no need for two types of tren at all. Winstrol in a stack with tren, primo, masteron, and anavar is forgivable. I don't see the use for it, liver toxicity and also tendons issue aren't good pre-contest, especially if you try to still lift kinda decent poundages to maintain size, IMHO.