First and foremost, Max Barran is a businessman. That's not a bad thing at all, to begin with; but yet, there are just several different ways of doing business. Max is only interested in always making the largest possible profit.
And this means: he couldn't care less about the circumstances, under which his gains are achieved. As early as a child, one has made to him utterly clear, that only financial success will lead to personal prestige, and Max is very pleased with himself.
His sister is not. She considers him as ruthless and obstinate and has tried for years to appeal to his good qualities. But Max, if he wants, can be deaf in both ears.