I'm sorry I didn't know your dad, Robert, but at least I can provide you with some historical information on the 41st Infantry Division .
It was made up of National Guard units drawn from Washington , Oregon, Montana and Idaho.
As finally constituted, it included three Infantry Regiments (162nd, 163rd, and 186th), and four Field Artillery Battalions (146th, 167th, 205th and 218th), plus other elements.
Activated into Federal service 16 Sept 40 at Portland, Oregon, it trained at Camp Murry, Washington, Fort Lewis, Washington and in California.
It departed San Francisco P/E 19 Mar 42; arrived Australia 13 May 42; (Probably landed at Port Adelaide,Australia); landed and engaged the enemy at Dobodura, New Guinea 25 Jan 43; returned to Australia 29 Jul 43 for trainig ; arrived Finschhafen, New Guinea 20 Mar 44; assaulted Hollandia, New Guinea 22 Apr 44; asltd. Biak Island 27 May 44; arvd. Mindoro, Philippines 9 Jan 44; asltd. Zamboanga, Mindoro 10 Mar 45, fighting on Palawan Island and on the Sulu Archipelago; arvd. Japan for occupation duty 6 Oct 45; inactivated there 31 Dec 46.
New Guinea, Luzon, Southern Philippines.
Killed in Action743 Wounded in Action 3,504 Died from Wounds217 Rate of casualties, about 33 1/3%. Estimated days in combat, 250.
My reference for the above:
WORLD WAR II, ORDER of BATTLE, Shelby L. Stanton, author, Galahad Books, NYNY, publisher.
This excellent text includes a very good combat narrative for the 41st ID.
That is about all I have on the subject.
I hope this fills in some of the gaps for you and your family.