When we work, we give something and receive something. When we love, the exact same thing happens. When we buy an apple, the exact same thing happens. Such exchanges of something are called interactions. You can take a look to references and my draft of a theory of interaction on http://ydor.org. It would be related to the theory of systems.
When two entities interact, each one can get a positive or negative benefit. Win-win is one of nature's amazing phenomenon. Under normal conditions, job/work is a win/win exchange. Your brother wins money, his clients win some service/product. Win/win exchanges end up in interactions being repeated.
The big problem regarding to earning money raises on win/lose situations. Win/lose is also a common result, which is perfectly achievable and positive on the short term (you can steal ONE wallet an perhaps pass unnoticed). The problem becomes on the long term: win/lose cause interactions to cease repeating. On simple words, your brother can get temporary high benefits from some clients which end up losing, but soon he will lose all chances to continue interacting with any other clients.
And here's the point to your question: your brother future commercial interaction trends depend on his focusing: to give (tends to win/win) or to receive (tends to win/lose). Imagine he's a doctor. Focusing on receiving will cause him to use less resources on healing (patients lose) in order to earn more (he wins). Focusing on giving will cause him to use the best resources on healing, despite minor earnings. When someone focuses on giving, the possibilities of a win/win outcome grow exponentially. When focusing on receiving, win/lose is sure to happen. Clients will lose, but on the long term, your brother will lose all clients, and harm definitely his reputation.
That means that working for money, in addition to be a waste of time, causes a social damage and leads to poverty on the long term. On the other hand, working to help the others, making minor initial earnings is the natural right way of making long-term big earnings. The practical difference lies on the intention: to help himself or the others. It is not a philosophical approach, but an economical behavior. The "giving" approach seems also ecological, since it is just an imitation of the behavior of natural entities.
The only way to make big money with permanent easy earnings is to cheat people and switch quickly to another type of business and habitats, repeating the process constantly, which is moreover the common approach of making big money (drug trafficking, pyramidal schemes, etc.). But usually this leads to heavy legal issues on the mid-term, and a possibly a big frustration, since the person cannot develop itself, but live fleeing formal and informal justice.