Hello Cheryl. I find that this is a big issue with many families. Sometimes it is impossible to find out where the problem lies. Most of the time it is generated at home from the parents and their relationship with the rest of the family.
There seems to be some underlying issues with the adults of the family. Someone might not have treated them kindly and they shy away from those family members, and keep the children away from them or have no kind words for them, which is reflected in the family relationship. A sense.of coldness is generated throughout the family .
I have found that some parents are cold and show little love which is passed on to their children, therefore the children don't know how to express love and caring. It is never to late to learn.
You are not responsible for their behavior, especially if you don't know the reason. but you have to try to reach out, if that makes you feel better. If you don't get a positive response, then move on to make sure that you create the kind of relationships that you want in your life and pass it on to your children and family.
Don't look to others to make it right for you ,make your own caring and loving life.