The 16-year-old, whose father and sister died in the July 28 crash, had been hospitalised in Naples in southern Italy, close to where the accident happened.
Her mother, who was also on the coach, is recovering in hospital but today refused further treatment until she is united with her husband and daughters, not knowing they are dead, the reports said.
The coach, carrying 48 people including children, rammed several cars on a busy dual carriageway after failing to break on a bend, before smashing through a crash barrier and plunging 30 m over the edge of a viaduct.