We don't know nothing about the Xbox sales, just that its probably down YOY.
The last number we got was shippment June-September, or March-June, where it did 1.1 million(shipped) Xbox 360+One against 3+ millions of the PS4.
This guy is overestimating the Xbox One's numbers. They probably finished 2015 with 17-18 millions. If the sales are flat, they sold a total of 24-26 millions this year.
It would have to sell 10+ millions in 2015 + 10 Millions in 2016 to get to those numbers.
The Xbox One started 2015 with 9-10 millions of units sold.