I have had to travel and access healthcare abroad. I think the most important thing for both healthcare and customs is carrying documentation with you. If she doesn't have one already, your daughter should ask her main doctor to write a brief (i.e. no more than a page) summary of her medical history and needs, inc current and past medications (if there is any chance it could be needed even if only occasionally it should be on there) and previous surgeries. It should also have clear contact details in the event of any queries (email addresses are most useful).
Any items actually travelling with her should as be in original packaging and labelled as Carrie has suggested. As it's a long haul flight its worth thinking about the temperature her meds should be kept; hand luggage avoids them getting chilly in the hold! I have travelled with meds and liquids for my catheters in hand luggage, and was able to access the healthcare system in this way without encountering problems. I hope the trip goes well for her.
