Henry Stark was a merchant from Sycamore Illinois. The "founding Colonel" of the the 52nd Illinois Infantry Regiment was Judge Isaac G. Wilson from Geneva, Illinois.
Wilson resigned before 1861 ended because of illness. Also, John Christopher of the U.S. Army, who mustered the 52nd, threatened to turn the judge over to a grand jury for overcharging the government for horses bought for the local calvary regiment. (see Fold3) https://www.fold3.com/image/299554224
Major Henry Stark and Lt. Col. Wilcox signed a letter claiming fraud over rations before leaving for Missouri. (see Fold3)
At Shiloh Wilcox was home sick and Stark was in command when the 6th dawned. By the afternoon Stark was "relieved" by Col. Sweeny from command. He resigned a few weeks later. The stories were that he was "injured" on the movement forward, possibly by a "falling limb" (not impossible given the descriptions of trees being felled by cannon fire).
Anybody know anything more? There are hints that Stark lost his nerve, not a mortal sin, imho, given what he must have seen on the way forward. He did not return to service. But having a leaderless regiment in the chaos did not help the Union cause.