Mrs. Egan's dad had just cause for mental/emotional stress from my reading of the military history of the 75th. Infantry Division.
Immediately after their landing at Le Havre and Rouen, France 13 Dec 44, they were rushed to the Ardennes-Alsace front (The Bulge), where the Germans had made all out attacks on American positions 16 Dec 44.
The division occupied defensive positions along the Ourthe River on 23 Dec 44. It was involved in heavy combat around Sadzot, after which it moved to the Aisne River at Grandmenil 5 Jan 45.
On 8 Jan 45 the division relieved the 82nd. Airborne Division along the Salam River, and attacked across it at Salmchateau and Bech. The division cleared the Gran Bois 22 Jan 45 and captured ASldringen 24 Jan 45, concluding its offensive.
There were many other engagements after the Bulge, which are adequately descibed in Shelby L. Stanton's WORLD WAR II OPRDER Of BATTLE", all of which would add to his problems, I'm sure.
Another reference I use is "2194 DAYS Of WAR...AN ILLUSTRATED CHRONOLOGY OF THE SECOND WORLD WAR", compiled by Salammagi and Pallavisini, printed in Italy, published by Barnes & Noble, NYNY.
In your reading you will find few if any references to the 75th. Inf Div., However, there will be frequent references to their major units like Army, Army Group, Corps etc.
I have listed below the 75th's Overseas Wartime Assignments, including effective dates.
12Army Group, 9 Dec 44 9th Army, 9 Dec 44 XVI Corps, 11 Dec 44 VII Corps, 22 Dec 44 XVIII Corps, 29 Dec 45 VII Corps, 2 Jan 45 XVIII Corps, 5 Jan 45 6th. Army Group, 25 Jan 45
Finally, the 75th. Inf Div included: 3 Infantry Regiments, (289th, 290,and 291st) 4 Artillery Battalions (730th,897th,898th and 899th)... plus other elements such as 5 Tank Battalions, 6 Tank Destrover Battalions etc..