The brilliant doctor was so grief stricken by the closing and demolishing of the hospital, he moved into the country side and bought a farm.
He decided to live out an ordinary life and wait for his eventual demise at the hands of the illness that had taken Kiri's and his grandmother's life, Old Age...
From then on, he turned into the unimpressive, unattractive, unintelligent, mess of a human being we all know and love, the Fat Farmer Doctor.