It really varies on the individual but I'm inclined to say, you never get over the missing and memories of a sudden death of a parent but you can recover. Time allows the hurt to lessen a bit but you will always miss them in your heart.
I don't think anyone really recovers from any type of sudden death. It's hard enough to deal with a death you know is eminent but when it is sudden, the initial emotion is shock and then grieving. Whereas in a death of a parent who has been sick or ill, there is no shock emotion, but initially grieving.