Clay,
Is Pfc. Ralph W. Butler your father? If so, he is listed on a roster assigned to Headquarters and Headquarters Company, 3rd Battalion, 253rd Infantry Regiment, 63rd Division and the 370th combat engineers. If your father's name isn't Ralph, he was not assigned to the headquarters company, only assigned to 370th.
I had joined Marion Chard's website and unfortunately misfiled an email that she had a subgroup for the 370th engineers and email addresses.
I also noted that you had posted a question regarding the Dachau Concentration camp. You father probably saw the Dachau
"The Death Train"; my father had taken several photos of this train. Google "Dachau Death Train" for photos and information.
Also, your father probably entered part of the concentration camp, I know my father did and took several photos.
Hopefully we can exchange additional information and stories regarding the 74th AAA and the 370th.
PS: presently trying to locate a copy of the 74th AAA battalion history through AHEC.