There isn't any helping the tone, really. The gesture might be nice, but it has essentially come in the wake of a family crisis and he cannot bring himself to be happy about it.

And unfortunately for Lazarus, a quick look is all it takes for Nathan to realize what condition he is in. It is not due so much to his observational skills than it is to personal experience. He has seen enough hangovers to recognize one when it is put before him, even with the efforts to dull it. He knows what they look like.

But he will try not to mention it. "... I think after would be best."