Older Bro Vs. Younger Bro's Birthday

Do you remember first learning the concept of sharing?  Our son is facing one of his worst fears:  Someone else' birthday!  I can't get over how troubling it seems to this 4 year old that he will not be getting any presents on his brother's birthday.  I wonder if we aren't all a little like this when someone else is receiving something good?

With some subtitles, because even though he's 4; some things are only discernible to his highly intellijent parents.