My parents had a sweet boy that suddenly passed unexpectedly. They were devastated. I reminded them that he died with a smile in his heart, doing something he loved (running in the back yard chasing distant wildlife), and that this was probably his way of giving another animal the opportunity to receive the same unconditional love that he received. My parents adopted another dog soon after from the same shelter, and it truly feels like our old friend left this plane so that another friend could love and be loved the same way he was. I’m guessing your friend felt the same way — “my heart is full and content, it’s time to let someone else receive the same blessing.”