General Fredrick Funston was the Commander of the US Army Southern Department during 1914-16, he was General Pershing's superior during the punitive Expedition and was in command of the border during the 1916 National Guard Mobilisation on the border. It was under him that the bugs of that mobilisation were ironed out and the NG trained up to a reasonable level during their months on the border. He was favoured to lead the AEF but died of a heart attack at age 51 on 19 Feb 1917, so his subordinate Perhaps was appointed to lead the AEF.
WI Funston didn't have the heart attack?