By Fergus Walsh, Medical editor & Camilla Horrox, Global health producer

It’s 10am, and in a little over two hours, Wayne Hawkins will be dead.

The sun is shining on the bungalow where the 80-year-old lives in San Diego, California with his wife of more than five decades, Stella.

I knock on the door and meet his children - Emily, 48, and Ashley, 44 - who have spent the last two weeks at their father’s side.