Yes, according to Buddhist beliefs, illness is the natural settling of karmic debt. When third parties like yourself, wade in and “meddle” in that repayment process, you will have to bear the burden of the debt. The better you are at it, the more karmic burden you will end up having to shoulder, either this lifetime or in future lives. Such is the Law of Cause and Effect.
You may read more about this in our Monthly Dharma Talk section on “Healing Illnesses” available on our web site, http://www.chanpureland.org/