The fairy is meant to be used a support, not as the main healing. Its like a 2nd...side healing set. I myself am only level 31, but I have had no issues healing. Usually I use Eos and heal on my own. When you switch to Scholar you get a nice boost to Mind so that it surpasses your Intelligence. Youll mainly use Physick/and or Cure, and Adloqium is meant to LIFT stress on a character that taking a bit more damage. I usually use Adloqium on a person to give a small window of opportunity to put my attention on someone else. The fairy tends to do a good job on her own, and supplements my own healing :3. Plus as someone said before, that AoE HoT spell is helpful with poison.
As for when I solo or need support I combine Selene with Cleric Stance, making my attack spells stronger so I can do damage when I solo.