His Individual Personnel Deceased File (IDPF) should provide all the info you seek and enough to enable you to locate and access other sources. The current address is:
?Total Army Personnel Command ATTN: TAPC-PED-F (FOIA) Alexandria, VA 22231-0482
All you need to provide is his (1) name and (2) date of death. Any other info may be helpful but not really necessary. There's no charge but there may be a wait of up to eight months, depending on their workload.
A simple note, something like: "I'd like to have a copy of the IDPF of Woodrow Henry Bennett who died in Europe during World War II on or about (date of death)." Keep it simple. This isn't rocket science and the people at PERSCOM are very adept at what they do. You can use a post card.