90th company k infantry ww11? Any info on these men?

My gf was in the 359th infantry division, company K and he seen actual combat in WW11 and I’m sure he then went into the 90th division in June 1944 or possibly March of 1944, he was in the European Theater and Rhineland, and others as well. I’m trying to figure out how to determine exactly his role and did he get put into another platoon? I’m at dead end