Well first off Russia as a different set of rules than any American Prisons and when it comes to closure for the victims families death is better than staying in prison due to certain conditions but life without parole is the next thing to death sentence so even if they mess up and for example kill a cellmate of assault an officer they will be given the death penalty but there are different types for an Inmates death (depending upon the state and crime) in Texas and Alaska you can choose a firing squad or in North Carolina you can choose a gas chamber but the most common method is Lethal Injection.
Sounds very clear and literal. I would limit the number of times "supporters" was stated. (Maybe you could replace it with a word that has the same meaning so that your text could be more diverse).
Though he is not satisfied with his life and happy with it still he believe he would have done more with his life if he had realize earlier or known earlier
Explanation:Now it seems he has no chance in life again because it to late to change his fate or destiny.