It happens :) My elder son (almost 3 year old) and younger son (7 months), though the elder loves the younger very much but when come to playing toys he is reluctant to share with little brother even for the pieces that he does not play. There is nothing we can do other then educate him over and over again to share with others. For my case when my elder son forcefully take away the toys from little brother, I would always tell him to share and want him to give to the little brother, and on behalf on the baby I thank him. After play i guide the baby's hand to return the toy to him. To this day he is still not willing to share until I ask him too, but I am trying each time