Hard to predict the reaction he will have. Some poeple who take medication feel sick during the liver flush and release fewer stones. Few fare fine. They may have to do one to see how they do with it. It isn't dangerous for them, if that is what you ask. People on pace makers may do well changing their diet (avoiding animal proteins and other foods, see Timeless Secrets of Health & Rejuvenation) to regain proper heart functions.