By the way: while looking for Mr. Walking
Eagle and your grandfather's unit, I came across the following:
History of the 363rd Infantry: One Regiment of the 91st Division in World War 11. by Ralph E. Strootman. Publishedf 1947 by Infantry Journal Press. Original from the University of
Michigan. 354 pages.
Your grandfather is listed by name in one entry (can't read the page online, though), and Walking
Eagle is included, too.
I see used copies of the book are offered for sale online, and copies are in many University libraries.