Having been in this scenario over the Atlantic, I have to say that I did not have a cabin crew read out any checklist nor help in any cockpit duties. Her only responisbility was to look after the incapacitated captain.
Our cabin crew had never been taught to read a checklist nor understand when to challenge or respond. I only had 400 hours on type at the time of the occurence, but felt that flying single pilot was safer than having someone read a checklist for me for their first time, while dealing with an incapacitated captain (high stress level for her).
I believe it should be at the pilot's discretion to use any means available to them at the time, in order to manage the situationa and workload. However, to make it an SOP...
