Should I notify sibling of father's condition even if he has not seen him for 1+ years, only scattered phone calls?

I think that one of the pluses of modern communication via text or email is that it is easy to dash off a brief note without obligating yourself to a long conversation, I think of it as the modern day equivalent to a post card. So, I would send a very short note mentioning his deterioration and leave it up to brother to ask for details if he wants them. No need to let yourself be drawn into a back and forth conversation if it would only be an argument.

Are you obligated? Not at all. Should you? I would say yes. At least once. Then it's up to your brother to keep in contact and ask how your dad is doing. But considering he doesn't now, why would he in the future? He doesn't seem to care.

I'm in a similar situation. One of my brothers is exactly the same way. He doesn't keep in contact. Maybe on some major holidays. Maybe. When mom or dad are in the hospital, I call him to let him know. I regret it each time. He just storms in and tries to take over implying it was all my fault. But when the rubber hits the road and we actually need him to help out, he's just full of excuses. He can't be bothered.

I would inform your brother about your father's condition. He does have a right to know. In my experience, one needs to put differences aside for the sake of a loved one. It is stressful enough, and you certainly do not need more stress from a sibling. My close uncle was diagnosed with lung cancer and did not have much time left on this earth. The sister, my cousin would not call her sisters to let them know. It was a month, and finally I told her she needs to let her sisters know about his condition. I decided to call one sister who then called the other. My cousin was so upset for not letting her know sooner. The two sisters have not spoken to the father for a few years. It was not my cousins place not to tell her sisters. They did have a right to know. The sisters did not speak to her for twenty years, and now recently they are speaking once again. Forgiveness is so important. It may take some time to forgive, that is human nature, but in the end one will be better off for it. I always inform my siblings when there is a family crisis. I call or email and explain the situation. I even ask them for some advice. I keep them well informed. I do not have to do it, but I feel it is the right thing to do. My thoughts and prayers are with you.

I would keep your brother informed of your father's condition as it deteriorates, even if it's via text or voice mail. I don't know that you are "obligated" to do so, but I'd want to know if it were my father who was dying. That's how I always gauge things....by asking myself how I'd want things to be handled if it were me.

Sending you a hug and best wishes as you go thru this difficult period with you dear dad