Why can't Paul understand Mrs. Kemmerich's anguish?

Paul has been surrounded by violence and death to such a degree that he is numb to it. He can no longer express his anguish because seeing his friends die before him has become second nature. This numbness is necessary.... how can a soldier survive if he gives into the loss? Hardened by his experiences, Paul can't understand the depths of anguish he sees in Mrs. Kemmerich.... if he did..... he wouldn't be able to return to the war that awaited him.

Kemmerich will stay dead whether she knows about it or not. When a man has seen so many dead he cannot understand any longer why there should be so much anguish over a single individual.