To sell his house, he takes his father to a nursing home and, when he comes back for more, this happens.

The sadness of losing a child

Gavin wept at losing a family bond that he now understood was more complex and profound than he had ever appreciated. He had been a son by choice and love, not by blood, a fact he had tragically ignored. His heart ached with regret, longing for a bond he feared had been broken. It seemed the mansion was empty, a monument to his lost connection.

The Lament Of A Lost Son