Dementia

Background
In the reboot series, Graham in his old age, suffers from extreme dementia (Alzheimer's or similar disease), and it begins affecting his personality, and it gets worse as the days pass, as he forgets details to his stories (memory loss), loses motor control (bedridden), sleep deprivation (insomnia, staying up late into the night), depression, irritable outbursts to his family, and starts to hallucinate (see ghosts), and fearful pleading. As well as going through the stages of grief as he comes to terms with his imminent death.