My personal favorite brother is the kind that can help you in an emergency. And it is the kind that you can confide in each other without caring, and help release the pressure without feeling the psychological burden, especially in the future. Everyone has something good, they will share it with each other and laugh at each other's embarrassment. This is the way I get along with my envious brothers. But this is still a minority. Many people are just based on blood relationship, and some people often don't chat together because of the big age gap.
Personally, I think the reason why brothers have a good relationship is because their parents' educational guidance and loving family environment make them accustomed to this growing environment and let them release their love. We can often know the situation of a family from the children's state, so if there is love between brothers, we often have strict requirements on the quality of parents.
In my personal opinion, the best state between brothers is to understand each other, be friends and help each other, and will not look down on each other because of their future achievements or work. Two people can study together and make progress gradually, which is a better state. Of course, this kind is relatively rare, which is related to their family environment. Many people will gradually neglect their brothers mainly after marriage, so their feelings still need to be maintained. Being good before doesn't mean they are the same.