When your child refuses to share his possessions, he is acting his age. He will be very possessive about his toys. It takes some time for him to develop the sharing skill.
What you need to know
At this point, your child may tend to show a toy to his friend but may not let go. However, this is a big step towards sharing. You can practice taking turns at home with him. For instance, “You throw the ball and then it is my turn.” Never reprimand your child for not sharing. On the contrary, make him realize you are sad for not sharing the toy with you. Let him work it out. When he is with his friend, let him figure out what happens when he does not share his toys.
Praise your child when he shares. This goes a long way in building his social skills and self-esteem. Practice, patience and polite teaching will help your little one to share and take turns.