Could Dmitri still be alive?

He's worth a lot more to the Russians alive than dead. He will have been beaten, tortured even, but kept alive for future use...as in the spy swap hinted at.

I think Dmitri will always blame Henry for making him a spy and having to endure what he had to go through. And he thinks that Henry can never keep his promises and considers him as an object. His first reaction when he saw him at the was to make him realize "I owe you nothing, I'm not going to ease your conscience and be grateful". Then he saw Elizabeth and probably realized that Henry had to intervene and beg POTUS himself to have him free. I guess Dmitri has mixed feelings towards Henry: he sees him as a symbol of American imperialism that can buy and control anything but also as a father figure who can protect him when necessary. Since Henry has failed him several times but also helped him on many occasions, Dmitri hesitates between his admiration for his professor and his rejection against his master.