Lucius does know himself well enough to know how toxic anything like pity can feel - no matter how pitiable the situation might actually be. The Lucius before him still has his Narcissa and his Draco, at home, and he is firmly of the opinion that anything short of losing them can eventually be recovered from. He needs to believe that.

It isn't as if he's entirely green - he did grow up during a war, and it shaped him, but into nothing like what he sees. (Not yet, an insidious voice in his mind whispers.)

He doesn't call out to stop him. It seems that he and his alternate are likely to collide in short, painful intervals.