2012 Yukon xl 4x4 eating antifreeze?

[Pandabird]

Send an oil sample to a lab and have it analyzed.

Doesn't hurt to do the coffee filter test if nothing else.
One bleached coffee filter and one droplet of oil from the dipstick.
Let it sit out in the sun until completely absorbed. Should become an evenly colored blot.
Yellow or clearly brighter edges means there's fuel in the oil, dark dot in the middle and dark edges point towards heavily burnt oil.
And a paste-like texture to the touch point towards foreign substances like water.

There's also another household way to check for water in the oil, by adding a drop of oil onto a really hot surface like a hot electrical stove.
If there's water it'll sizzle. If not it'll just silently go smoke (not recommended in the kitchen).

 

[Doubeleive]

Doesn't hurt to do the coffee filter test if nothing else.
One bleached coffee filter and one droplet of oil from the dipstick.
Let it sit out in the sun until completely absorbed. Should become an evenly colored blot.
Yellow or clearly brighter edges means there's fuel in the oil, dark dot in the middle and dark edges point towards heavily burnt oil.
And a paste-like texture to the touch point towards foreign substances like water.

if one drop of oil shows all that then simply flipping the oil filler cap over should reveal it as well as a look inside the valve cover.
the filler cap should be pretty much bone dry unless the vehicle is only driven very short distances.