Xavius is a boss with a unique mechanic that resets mana and allows for spamming without being really punished. If you look at the logs, you will see that in most cases of 2 healing a raid of 10, one healer will be way ahead of the other. This is not a sign of better skill, it's caused by the mechanic. The one starting in the dream has a easy life, because of nearly inifnite mana. The other one should be careful with mana.
If she would be that high in stats with being second in dream, ok that would be astonishing. But with infinite mana and a lot to heal, it's easy.
Enter content that's meant for your ilev and let her spam with haste focus and you will have a nice time wiping.