The injuries were different from anything before gas, for one, terrible facial injuries, and shell-shock (that we now call PTSD) for another. The story of your great-uncle made me cry.
Countless movies (and books and poems) from All Quiet on the Western Front onward celebrate and mourn men in the war. Because womens stories are untold or, if told, forgotten, Ive been collecting the stories of the women who went to that war as nurses, ambulance drivers, drivers for officers, and whatever else they were allowed to do. They died or if survivors were maimed, just as the men were, but as Pat Beauchamp found out, the hospitals and rehab facilities were all for the great numbers of men and they didnt know what to do with a lone woman, so she had to fight hard to get her due.
I find these books kind of randomly over at Project Gutenberg (gutenberg.org) by checking their new acquisitions. The first one I found was Fanny goes to War, by Pat Beauchamp, a British girl who joined the First Aid Nursing Yeomanry or F.A.N.Y. She lost one leg and almost lost the other. After that first book, I kept my eye out for others.
Britain suffered hideously, losing nearly a generation of young men, which accounted for the number of lifelong spinsters (ever so kindly referred to as superfluous women ) in the decades following the Great War. The military sent brothers together, school chums were encouraged to join together, whole villages of young men sent in the same unit for the sake of comradeship all lost, often at one blow. Punishment for anything considered cowardice or insubordination was absolutely savage as apparently was the case for US soldiers as well.
I admire that you went searching for your uncle, both as a child and as an adult. Thank you for sharing his story here, with us. I hope he found his peace in the woods, in Nature. I hope he is at peace now.