Another person has tuned in to help us out, hope it helps Gina!

Gill colour should be cherry red. Any lighter and it could be ammonia/nitrite poisoning or anaemia.
Did she test for ammonia nitrite nitrate and ph? Also testing from the tap is a good idea too.
Still dont know what the set up is, we need the size of tank/vase and filtration used and how long its been running.
If shes only doing water changes once a week then it could be a bacterial disease.
Does she use water conditioners as well.
sorry if these have been asked already.