Sadly, it seems to me as if Harry goes on and on and on about his traumatic life as if he is the only one who could possibly have ever suffered the loss of a much loved one.
I agree that the manner of his Mother’s death was very tragic indeed. However, he is not alone in losing someone special in such tragic circumstances as a death caused by reckless driving.
In addition, many people have lost loved ones in other terrible ways when they themselves were children - the death of a parent, a brother, a sister, etc. (I, along with countless others, fit into this category), but we have to pick ourselves up and try to get on with our lives. That ache never goes away, the wondering of “what might have been”, but dwelling in self pity for any length of time, is totally counter productive and damaging. I also strongly believe that our loved departed ones wouldn’t wish us to live like that. I wish he could come to some sort of terms with his terrible loss and realise that he isn’t alone in such loss.