In the Trinity, you have three relationships which are infinetly integrated within each other, yet distinct.
Each person is what he is for the other: He is Father of the Son; Son of the Father. One can not be without the other and the being of one implies the being of the other, and this eternal bond is the Holy Spirit. Perfect self-gift only native in God. Self-gift build into the very being of the person for he is a relationship within himself.
God granted this gift to man. What you did not notice is that one family is supposed to be one 'man' but sin divides it into many 'men'. Extra love required to see this. In one family also, each person of the three has become a relationship within himself or helself, and there is no going back. Once a father, always a father. once a mother always a mother, once a son/daugher always one. And a father implies a mother as well as a child. None of the three can be without the others. Even death can not remove these identities/bonds. Nothing can. They are eternal identity and with this eternal bonds, you have one being/man.
Sin bring selfishness, and causes people to see persons as separate 'man' in themselves and by themselves forgetting that they are what they are by the others. If you are a father, you are a father by the son/daughter and the mother, not by yourself. If you are a mother, you are so by the father and the son; if you are a daugher, you are so by the father and the mother.
When you realise that you are one with them, then, there is no more counting yourself as if you are one unconnected entity beside them.
Nop, you are one and in a way your destinies are bound together exactly as if you are one being. There is nothing that happens to the others which does not affect you personnaly. If this is the case, that's because sin has divided the family deeply.
Only God can separate the destinies of the persons connected with family bond. So if one choose a life of sin, the others will not share the consequences if they were 'born again' in the perfect family which can not sin and affect him negatively: God.