I agree with Altra that this sounds like a purely emotional and probably ignorant reaction of a family who is trying to have good intentions. It also sounds like you did a pretty good job of explaining to them. I've had this issue too, and what I explained was that Coumadin is a medication that you're either on or off, and that there can't be a set dosage because each patient will respond differently. We wouldn't want to just randomly decrease the dose, because then there would be no benefit in taking the medication at all. Emphasize that we are trying to do the best thing for the patient, and ensuring that they get an appropriate dose is always the best thing for them. Way to stay professional.