It's probably not. Assuming 850k / hour on average, a totally realistic number for jar farm, and 24\7 botting for 4 weeks you're already up to 570m after 4 weeks, subtract 10m for downtimes and you got 560. Assuming he switched directly to Sarkoth and made 15m / day for the 3 next weeks ~875m would've been possible. And seeing how that figure assumes he was not botting for a total of 7-8 days. And that he could've had a higher GPH on both Sarkoth and Jars then 850 / 600 that I calced with. Even more would've been possible.
Pretty sure he's basing his opinion on the "other" stats in the picture. I.e., the elite kills and lifetime kills.