I can not comment on the necessity of the defibrillator but I am sure surprised that a doctor would treat not to describe medications anymore to press someone into undergoing a surgery.
Oh lord, that is crazy in my opinion to withhold medicine. I can understand the concern but if he hasn't fallen into VT ever not sure why they are so hard pressed to put in a defibrillator. Did your father see a new doctor there? I would suggest seeking a second opinion before proceeding but not sure how much flexibility he has with the VA. I wish I had an answer for you. This is really something he needs to decide for himself but I find it completely irresponsible that they would threaten to withhold lifesaving medicine. I would think that would leave them open to lawsuit in my opinion and you could threaten it if they continue to refuse the meds even if he declines the defibrillator. In any event, I might also post this in the heart disease section since he has cardiomyopathy on top of the afib. You may get a better answer as to why a defibrillator was suggested which may have more to do with the heart strength then any other factors. Best of luck sorting it out. Please keep us posted on how he is doing.
Sorry to hear about your dad's worsening heart failure. His case is probably very complex given his AF and cardiomyopathy in terms of slowing progression. Heart Rhythm society has guidelines for scoring the appropriateness of ICD implants and it takes a computer program to go through the scoring so I suspect that a verbal explanation from his EP will be just as complicated. Also, medications that treat the AF may promote VT and vice versa and they tend to lose effectiveness over time. Perhaps the doctor is anticipating that your dad's medications may no longer be worth the risks and that an ICD is needed to prevent SCD. Beyond that, a heart transplant maybe the answer if he still has good life expectancy. Nowadays, the best EPs would try to stop and reverse progression much earlier via medication plus ablation, the technology and understanding has come a long ways in 20 years.
I think there must be more to this story/condition or the daughter and father don't fully understand the situation which of course is easy to understand.
As for the defibrillator, I just had one implanted 2 weeks ago and it's no big deal although I would certainly have rather not gotten one. 60,000 people a year have this done.