Can my dad who is 92 and has a pacemaker and defibulator still die from heart failure his arteries are beginning to clog up again?

Yes: We all die from something. The ppm/aicd work to regulate rhythm and rate. CHF is more a disorder of inadequate "squeeze" by the muscle. "clogged" arteries can lead to heart attack / infarction, which is another problem altogther. Hope this helps.

Yes: Defibrillator/pacemaker does not change the heart pump function, though a biventricular icd may do so. Prognosis in advanced heart failure is extremely poor.