Financially which of the business majors has the highest salary ceiling? I hear people saying tell him to study business law or business management. I don’t know which one of these is best for having a high income with a bachelors or masters degree.

Frankly, he should study what interests him, not the one with the highest ceiling, because if he doesn’t enjoy it, it is unlikely that he would do well enough to make anywhere near the ceiling. If he were to look at potential salary, information systems and finance would be the highest-earning. Management and business law would be among the lowest (people think that because lawyers make a pretty good salary, business law would be good; the problem is that with this degree, you don’t become a lawyer, so there is no comparison).