Someone who is undeserving and yet seems to be successful could be on account of good deeds he has done and GD is repaying him in this world so that he does not have to reward him in "the hereafter".  At other times it may be to prepare for the righteous son that he is destined to have and the money will be there for his inheritance. pg 391 When a Jew does a Mitzvah properly, even if he is unaware of its mystical meaning the higher worlds gain tremendous benefits. Each mitzvah is Mikadesh the higher worlds and "gives power to GD" Gate One, Chapter 22 pg 73

A "Good man" who H'shem tries with difficult times may be to show the drastic difference in his reaction than of the "wicked" ,in the fact that he remains  true and devoted to H'shem.  Another possible reason is, He may be receiving a punishment for having not had enough Hitlahavut, (zeal) in serving the Creator and disapproval in the ways of those who disobey Him. pg 391 Nefesh Hachaim Since the completion of the Talmud there may be nothing added or retracted from the Torah and we must keep to the letter of the law. Gate One, Chapter 22 pg 72