God's Prodigal Family: Old Brother (Luke 15:11-32 (LD 51)

When we ask our heavenly father to forgive us our debts we are also asking that we forgive our debtors meaning those who sin against us.  The reality is that there is a cost involved with forgiveness and we might not always be willing to bear the cost of it.  What is more, the bigger problem is that we might not think that we ourselves need that much forgiveness.  So, what does the older brother or the older son tell us about forgiveness in the kingdom?  Why does Christ tell us that this man had two sons?