'gratitude' is a positive emotion thus certainly a way to deal with death (as you described) because it takes the emphasis away from "my loss" and places the emphasis upon what "another" has given to you
the word Buddha used for 'gratitude' literally means: "what others do for me; what I must do in return"
as you were more focused on acknowledging the merits of your father (than the loss to yourself), you suffered less (I would imagine)
Buddha taught to his lay followers (who have not realised the higher path) that they should make offerings on behalf of their parents after their parents die
