Why would the big brothers want to buy a house for that kind of girl? This is because by buying a house, the big brothers are able to achieve control over the girls. Usually, the big brothers don't buy a house in full, but only make a down payment. As the monthly payments continued to accumulate each month, the girls could not afford these expenses on their own, so they had to rely on their big brother. In this way, the girls will follow the big brother more steadily, increasing the control of the big brother. 
This relationship seems to be full of affection, but in fact it is full of calculations. They mistakenly believe that the relationship between people is just an exchange, and if the relationship is defined as an exchange, then the girl is likely to betray the adult once she has the opportunity. Because the heart of this relationship is to control, not to give real feelings.
Understanding relationships is crucial, and with in-depth insight, you can discern who is genuinely in your heart, who is hypocritically manipulating you, and who is willing to give your heart to you. 
Because of all this relationship, to understand a person's true emotions and information, it is necessary to observe carefully in the process of building a relationship with them. Don't just listen to what they say, it's more important to look at what they actually do. 
Therefore, these young girls must understand the rules of the relationship and not fantasize about relying on a big brother to live a stable and perfect life, because it is almost impossible.