Well, I'll start by saying a few things about it first. The novel is about a character who experiences traumatic and well as tragic hardships through life. He loses his brother who is the only person in the world who meant a damn to him by careless mistake. He grows up finding out the hardships of life. But he gets shaped into this psychotic, power-hungry, narcissistic man because of the horrible memories that plagued his youth.
The story takes places in 1975. The way the story is set up is different though. In the beginning of the story it talks about the main character, Donald, from the perspective of death. It starts with a scene of a funeral and the guest are all at the funeral talking about Donald. There's just one thing odd about the guest. The only people who were at his funeral were people who despised him.
The character made a name for himself as an Irish gunslinger and kingpin during the prohibition period. He also manages illegal businesses and profit sharing. He lives his señor years as a wealthy man because of this. He had to make unruly decisions in order to progress through his criminal business.
The story builds up from what is essentially the end (if speaking in chronological terms). It ends at the beginning (If that makes any sense). It's basically a star wars way of telling the story. That's the best way to put it.
So what do you think so far?

There are no new ideas in fiction. Whatever you can think of, someone else has already done it. But they haven't written it the way you would write it, so it all depends on how you write it.

A novel like this could work, but you need to keep a very tight grip on your timing, and even though it is running in reverse, the normal factors apply. What is his goal (what he wants)? Why does he want it? And what is stopping him from getting it?

In a story that revolves around a single central character, you are going to need strong conflict. That means not just dramatic things happening to him, but things that make him change in order to cope.

Having him shaped by tragedy in his youth is good, but you need to add something extra, most people experience tragedy and don't become criminals.

If you were to sum up your novel in ten words, what would they be?

Another author who wrote an awesome book in which the end turned out to be the beginning, and had a reverse chronology going throughout the book, is Anita Shreve, The Last Time We Met.

Like Eileen said, keep the writing tight. It sounds like the kind of book in which the dialogue can effectively move the plot along. And be sure you let someone proofread/edit it.

It already sounds like there is too much going on in this book. I say simplify.