From what I have seen, grieving is a very individual process. And people get "stuck" at various stages.
I agree with several above who commented on setting aside those memory's of the accident. Life shattering as it was.
Dig deeper, pull up other memory's. Stick them on the wall. Simple things, your friend smiling, doing something not so smart. Anything but those memory's of that day.
Just put those away for another decade. One where the sharp raw edges of loss have worn smooth. And you can pull them out and look at them with less pain.
I won't say no pain because I don't think that will happen in this life.
Yes you are stuck with this. This IS.
The pain is real. You have 2 choices.
Let it screw you up to where you follow him into death.
Or learn to live with it.
Be Blessed.