I've always thought Dimitri and his sister Marie had one of the saddest stories in the family. His mother died giving birth to him, which probably caused him some guilt, and then his father chose to marry someone the Tsar didn't approve of. Dimitri probalby felt at some level that he wasn't good enough for his father. Sergei loved them, but he was apparently also very strict and Ella was sometimes cold. Poor little rich boy and girl!
But Dimitri was also apparently dissolute and aimless and unable to make a life for himself after the Revolution.
I think the murder of Rasputin was quite brutal and sickening and in the end it didn't do a whole lot of good. But in 1916, if I were in Dimitri's shoes, I might have thought it was necessary to save my country and the Romanovs. I think Dimitri was probably right there and quite possibly fired the fatal shot, despite Felix Youssopov's reticence. It may have been the one courageous act of his life. Who knows what would have happened if he had done it a year earlier? Tsar Dimitri and Tsarina Olga Nicholaivna? Their plan to marry him to Olga and put him on the throne doesn't sound bad to me. He could hardly have done worse than Nicholas.