'He's my son'

I taught him how to walk, his mother stayed awake hours for him when he was sick, his first words were music to our ears, we sold our possessions to give a better life and better food, we worked hard to earn and fulfill his desires and wishes.

But why did he left us?

I never told him he wasnt born to us but we never felt the need to tell him and now our son, he left us. How can money change a person to this extinct. Ya Allah? Why did this happen to us?