When the Avatar found her in Ultima IX, she was busy with tending to her wounded husband. She'd lost all confidence of her healing powers after all the horrible things that had happened in Valoria. When the Avatar later returned, Meranthon was having a heart attack and Liselle still didn't think she could help him, so the Avatar tried a healing spell. When that didn't work, Liselle finally tried on her own, managing to stabilize him.
However, in a cruel twist of fate the Guardian right then remotely killed Meranthon to mock the Avatar, leaving Liselle with nothing but grief.