I'm really a bit confused by a number of things here, maybe OP could condense the first post. Nevertheless, if you had one continuous ticket (did you?) you would have a claim under EC261 with Air Malta. If you had two different tickets for the journey (unlikely as then there would have not been an effort to get her to EDI) you're pretty much on her own. There would also have been a duty of care requirement. I'm a little surprised an 18-year old couldn't figure out at the very least a discussion with the information or help desk. But I think there are some details missing here.