Basically what everyone else said. Blind Diogenes, send the mother to a convent, and the Armenian should be exiled; whatever happens Diogenes should not be exiled, as he is certainly capable of seeking foreign backing for his claims to the throne. In this way Diogenes is punished and sets an example for others, the mother can't be used by political enemies any longer, and the Armenian's freedom shows the emperor's mercy and as he's a minor noble doesn't offend the Armenians like a harsher punishment might.