Who is Ellen McDonald from Mercy and what is their importance?

Ellen McDonald is Cam's mother. After the death of her husband eight years before, Ellen became interested in mystical sciences, including herbal potions and dowsing rods. Cam finds this behavior embarrassing but indulges her, because he loves and respects her. Allie, on the other hand, likes this side of Ellen, because it makes her happy. Allie helps Ellen as often as she can, supplying the herbs and flowers Ellen needs for her various healing potions.