Sociality

My son is not good at greeting people except family. However, he want to play with someone else. He seems feeling lonely.

I heard that human-beings and Bonobo(a spicies of Chimpanzee) can not lose social relationship, if it is lost they become weak mentaly.

Now I am afraid it. He want me making relation more. But is it enough for him? Maybe he would get more relationship with other kids. What should I do... .