If they dealt with that fake memory and left better, I still don't see why it mattered. Though, those sound more like hallucinations or delusions than a false memory.
In the short term it's not very damaging, but it will cripple them later in life as false memories can very well damage a persons reputation.
If you go out to dinner with some lovely individual who believes their dead great aunt talked to them on one or more occasions, would you really go out with that person a second time?
People have all sorts of crazy sounding stories, partially because so many of our memories are fake, and it doesn't cause huge issues. And if they can't realize that their problems were impacting their memories I doubt they're truly over them.