Fern was a human who lived on Earth at the time when humanity relied on intelligent clothing to perform tasks for them and make decisions for them. The Seventh Doctor gave Fern a suit and tasked the suit and Fern with a job — collect all discarded suits and place them in a building.
Eventually, Fern was the only human left. The suit took care of him and made decisions for him. It even healed him after an eagle attack and protected him from a bear.
Fifty years after giving Fern the suit, the Doctor and Ace visited Fern, but the excitement of seeing other humans was too much for him, and he had a fatal heart attack. The Doctor and Ace buried the suit with him. (PROSE: A Rose by Any Other Name)