For his WW2 service as aircrew, if you can establish a squadron number and approximate dates of service you can obtain copies of the squadron operational record sheets (F541) from the National Archive at Kew. These give details of every sortie flown, for example for a bomber squadron they would list each crew member, target attacked, bomb load carried, and captain's remarks post raid. This information is not available online and you either have to go to Kew and find it yourself (good luck!) or employ a researcher to do it for you (which is what what I would do).
Best of luck.