In a previous life I spent many hours at The National Archives at Kew where these records would be kept. The vast majority of RAF records there were never indexed and so languished in a fairly anonymous file and it took a lot of digging to find the right one. That said, I read in my copy of "RAF Records in the PRO " that "most files on post war campaign and bravery medals no longer survive". I would suggest that an application be made by the daughter to the RAF Records at the MOD.
https://www.gov.uk/guidance/request-...vice-personnel for the service file which may give some clues. Don't be surprised if it takes a year for a reply. The file is quite basic, postings and promotions etc.
Regarding the criteria for the award of the Air Force Cross. At one time (post 1932 I think ) the award was given "for exceptional valour, courage or devotion to duty whilst flying, though not in active operations against the enemy" I'm not sure what is meant by devotion to duty. I think some were for instructing 'above and beyond'
I used to know of a researcher who specialised in RAF records but I believe he is long retired.
Regards
