First, I'll say this guy is freaky. Super devoted, super clean. Honestly, though, he doesn't have super genetics.
I've been on the lifting scene for a long time. I've put in VERY dedicated stretches of months to years at a time and seen some pretty incredible results where many people, including friends and family, assume I am on something. I understand what it's like to have people who haven't gone more than a month without a donut, coca-cola or pizza making accusations and assumptions. I 100% think Sage is natural. I think he benefits from a very early start, with a great support system and he's just driven and dedicated.
He's most likely clean. Get over it, lazy babies.