I also think the right thing to do in a relationship is to talk about things with your partner. In this case, however, he already decided this is a relationship he doesn't want to stay in. "I don't want to be in this relationship anymore" is not a choice you make with your partner, is something you have to decide by yourself. The fact you think his decision of not telling her right now instead of waiting for a better time is "inherently the morally wrong" option doesn't make it so. By definition, there is nothing "inherent" about morality. 

I respect your opinion that he is wrong about waiting, but I disagree.

I don't see why you're bringing this up as a reply to my comment, though, since that has nothing to do with the point I was making. He decided to stay and support her. If he let her know he wants to break up that entirely defeats the purpose of staying. Acting normal is the logical implication of his choice, the only way he'll be able to truly do what he's saying he wants to do.