One document should be easily obtainable.
its the Form 1180 and you can get this by contacting the RAF Museum DORiS staff via their website and request a print out.
http://www.rafmuseum.org.uk/research/
Other documents may he held by the RAF Air Historical branch. A Form 765 is one thing to ask for and theres another inquiry form, Form 412:
I think they treat these as documents only for Next of kin and the only time I've seen one given to a next of kin it was a transcription where they removed detail of the crews serial numers and any details of injuries. not sure if the AHB will require proof of relationship from you.
http://www.raf.mod.uk/ahb/
The Forms 765 and 412 may not still exist.
http://www.peakdistrictaircrashes.co...trictl4601.htm