I will keep your friend in my thoughts and prayers.
Please know that when one is in a coma, they can still hear things, they respond to touch, talk, and music. I, myself, was in a coma for four weeks when I was thirty-three, and also have spoken to many, many people who have survived comas, and they have told me that the recall certain things, they remember many things. And almost all believe that prayer was instumental in the survival/recovery.
Eileen