If anything is online before there was an "online" it is so because someone had it, found it, researched it, wrote it then scanned it or transcribed it for posting online. For an individual unless he, his family or service members in arms posted thier information, experiences about WWII you will not find his or any "military online".
My local local paper started requesting the people of our county share and submit individual rememberences of WWII, and how it affected lives. You might check with the Beaver County Library if it knows of any such programs or collections for thier memories.
The NARA has Military service records-www.archives.gov- but there was a fire in 1973 affecting 80% of Army/Air Corp records. You can read about it and how to proceed.
The rest will be found in researching his military unit and finding those who wrote about their experiences or someone who researched Homer's unit.
You might find in an historical newspaper database either in the area he lived or in England, news such as you found in the old address book.