American died, possibly given assistance (5)
I believe the answer is:
aided
'given assistance' is the definition.
(I've seen this before)
'american died possibly' is the wordplay.
'american' becomes 'a' (common abbreviation - e.g. in organisation names).
'possibly' indicates anagramming the letters.
'died' with letters rearranged gives 'ided'.
'a'+'ided'='AIDED'
(Other definitions for aided that I've seen before include "given assistance" , "not under their own steam?" , "'Assisted, helped (5)'" .)