Nope, i am convinced he was given everything we know about his personality and behavior before the bombings. In no way does it excuse what he did but i think the idea of trying to turn him into the mastermind is ludicrous. He deserves all the punishment coming from him but if i were a juror i would vote lwop.
IMO whether he was the mastermind or not shouldn't have bearing on whether he gets the DP or not. He aggressively tried to hurt and kill people, multiple times. At the marathon, during the shootout (by trying to run over cops), when he was in the boat.
He stood there in that crowd and put that bag down, knowing that many people were going to get killed or hurt. If that's not DP eligible, I don't know what is.