Not much information. An FO had a low blood pressure episode on an early PMI flight in french airspace after he went to the loo. A flight attendant took his seat and read the checklists while the flight ended with a normal landing at the destination. Apparently the flight attendant had some "flight safety" training internally and will receive a thank you gift from the company. And VC stresses that pilots are perfectly able to fly a jet solo if needed and that that is part of their training while TUI said that the safety of the flight was at no point in danger.
The FO proceeded home on the next day.