These records relate to an individual seamen filed together in a pouch. These documents may include application forms, certificates, identity cards, (most with a photograph of the seaman) and cessation documents.
If it is the correct seaman he may also have a "Form CRS10" This would give details of all the ships, (together with dates and ports of Engagement and Discharge) he served on from early 1941.
I would apply to the National Archives to obtain the Pouch which will confirm his Dis A number. Once you have that we can procede with details on how to obtain his Form CRS10