Your grandfather was a member of the 165th Field Artillery Battalion, which at one time was a 75mm howitzer unit, one of three artillery regiments (156th FAR, 157th FAR and 165th FAR, which comprised the 44th Infantry Division.
The division was reorganized July 43, the new unit then included four Field Artillery Battalions (156th, 157th, 217th and 220th), with the original 165th FDA re-designated 167th FA BN, and henceforth was non-divisional.
The record is scant for this battalion, which became a 105 mm tractor drawn howitzer unit.
He was lucky to have been rotated out of the 44th Infantry Division, which ended up participating in three campaigns: Northern France, Rhineland and XCentral Europe, with 1,038 Killed in Action, 4,209 Wounded and 168 Died From Wounds.
Sorry, but this is all of the information I have available on his unit.