I usually deal in FACT - as opposed to SPECULATION - but I'll give you a list of what he's MOST LIKELY entitled to and let you do a little leg-work and determine for yourself.
He is certainly entitled to:
1. Air Medal (at least one strike/flight award based on the number of missions completed)
2. European-African-Middle Eastern Theater Medal (for 30 consecutive or 60 non-consecutive days service in that theater any time between 7 December 1941 and 8 November 1945) with at least one bronze campaign/service star (Air Combat, Europe; other campaign credits would have to be determined from official records).
3. World War II Victory Medal (for active duty anywhere between the dates 7 December 1941 and 2 March 1946)
4. The Flight Engineer Badge
IF he was wounded, he'd be entitled to the Purple Heart (one award for each occasion of being wounded - not per each wound).
IF he had a minimum 12 months active, honorable service as an enlisted man (most flight engineers were) he's entitled to the Good Conduct Medal (requirement is 36 months honorable, active service, consecutive or cumulative, but this is reduced to 12 months during wartime or periods of national emergency).
IF he entered active service prior to 7 December 1941, he's entitled to the American Defense Service Medal (IF he served anywhere outside the Continental U. S. during the same period he's authorized to wear a bronze clasp inscribed "Foreign Service" on the suspension ribbon of the medal and a bronze service star on the service ribbon).
IF he was permanently assigned anywhere in North, Central or South America (Alaska exluded) for at least 30 consecutive or 60 non-consecutive days or for one year while training for overseas deployment, he's entitled to the American Theater Medal (IF he was assigned or attached to a unit engaged in antisubmarine patrol duty off the Atlantic or Pacific Coasts, in the Caribbean or the Panama Canal Zone, he's authorized one bronse service star).
IF he was assigned or attached to a unit designated as an element of the occupation forces and met specified requirements, he's entitled to the Army of Occupation Service Medal.
IF he participated in the Berlin Airlift and fufilled certain requirements, he's entitled to the Medal for Humane Action or the Berlin Airlift Device (worn on the ribbon of the Army of Occupation Service Medal) or both.
Flight engineers often "doubled" as aerial gunners. IF so, he'd be entitled to the Aerial Gunner Badge.
The only way to determine for certain is to access official records.