Charlie, Bella's father, would also be a very likely helper. He's her family and has a natural instinct to protect her. He would be worried sick about his daughter and would do everything in his power to make sure she gets better, whether it's taking her to the doctor, making her favorite meals, or just sitting with her to keep her company.
Alice might be the one to help Bella. Alice is very perceptive and has visions of the future. She could foresee any complications in Bella's sickness and take steps to prevent them. Also, she's a caring friend and would be right by Bella's side, making sure she's comfortable and getting the right treatment.