I believe you can only use ground based heal over time heals. You can pop barrier on her too.
I tried to put illustrious continuously on her, which kinda worked most of the time. The rest of my party I healed with radiating & sanguine & bol & prayer & orb.
If she audio queues "heal me!" or similar I threw thousands of heals into her and whatever I did, I couldnt prevent her from doubling over.