Saving the fleet, the survival of their people, their civilization. Once they had fired his spirit, inspired him to fight. Once that had been a reason. Now, the feelings were distant, the concepts cold and meaningless. There was no reason left, no reason but one. These were her people, this was her fight and her sacrifice. So he would continue, he would soldier through - until the fleet was safe, until their survival was sure, until they had a home. Nothing mattered anymore, nothing but that. Whatever the cost, he would ensure her sacrifice was not in vain.
And then,
He would pay the ferryman, and he would cross the river.
And then,
He would lay down his burden.