ΔE 21.8, loose: different enough that you should pick on purpose. Khaki Drill is a little lighter, warmer than Desolate Brown.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 22). Khaki Drill is a little lighter, warmer than Desolate Brown.
The same difference applies the other way round: Desolate Brown is a little darker, cooler.
ΔE is the colour difference between our two swatch estimates: under about 6 is close, over about 15 is loose. Real paints also differ in finish, coverage and how they thin, so test before you commit.
See Desolate Brown on the colour wheel See Khaki Drill on the colour wheel
All matches: Desolate Brown equivalents · Khaki Drill equivalents