You do not want to be isolated
Until or unless you do not wish to be isolated, it is of considerable importance that you must have empathy. You must tell your kid to play with others and be a part of their happiness. You should never encourage their rudeness and tell them that they should be kind to other kids. Telling them to keep their toys away and not share things is not going to help; you should never encourage such activities.
It is often observed that people share their feelings with others when they are distressed or bothered by something. Usually, they share their problems with those persons who they consider worthy enough. Therefore, it is important that you should never let them down and give importance to what they have to say. It is of utmost importance that you listen to them carefully and share your thoughts as this will help in strengthening an interpersonal bond between you and that person. Remember that making interpersonal relation with some people is strongly encouraged, as you might need them for the same cause.
Tell your kids the importance of empathy
If your children lack the element of empathy, you must tell them to improve their ability. Tell them that it is not only important for socialising with people but it would be most required when they enter their professional life. A person without empathy is very unlikely to survive in this competitive world. It will not matter whether the plan to do a job or a business, the lack of empathy will always halt their way.
To grow your social circle
You cannot be in a group of limited friends all the time and thus you need to socialise with other people. Note that the element of empathy will help you in growing your social circle.