So is there a twist like in COLLATERAL BEAUTY?

I haven't seen Collateral Beauty, so I don't know what twist you mean. I also don't know how they're adapting this movie, but in the book, you immediately find out that Mack's daughter died, his father was abusive and Mack was responsible for his father's death. Mack's wife calls God "Papa," but because of his history, Mack has trouble reconciling God has both loving and a father. So, when Mack arrives at the shack, his expectations are turned upside down.