I have had problems with my father who is long distance from me, for quite some time. He hates me for reasons I don't understand. I won't give him my regular phone number, but I give him access to my magic jack number for emergencies, which is never plugged in and he leaves abusive messages on it and threats. He has 2 people taking care of him, more than I will ever have but they don't stop him from threatening. Should I cut him off completely? He does not go for medical care because he doesn't want to get caught with his alcoholism and I have called Adult Protective Services but they won't tell me if he's being taken care of adequately.
But since he isn't being logical, you should be. Change phone numbers. If you want, you could give the new phone number to his caregiver, in case of a drastic change in the situation (if you would want to be notified).