It is enough this that him be punished with lifetime in prison or not?
It would be if he'd actually been tried for it and it had been proven. It didn't come up in the case at all. I've no idea what the truth is regarding that area but it seems a little strange that they didn't pursue it. Perhaps they felt they already had enough.
They didn't pursed it because they knew that they will fail in it, as the charges and the evidence were all cooked up. It is not very difficult for the FBI to frame false evidence. They can just hack in to DPR's email account or chat account, and add whatever in the conversation history they want to add. This has happened in the past, and it will happen in the future as well.