Hi, I was just wondering what you decided and how your dog is doing.
The main thing that is necessary, at this point, is to get rid of all the black tissue, so that the necrosis doesn't keep spreading. Wherever the doctor has to cut in order to stop the process, let him go ahead and do it. He will have to leave a good margin of healthy tissue.
If your dog loses the pinna (the outer ear), she can adjust to it. To her, she will just feel like those dogs that have erect ears. You will adjust to looking at it, too, once you get used to it. The important thing is to get the problem stopped, so that it doesn't progress any more. You don't want this spreading onto the skin of the head.
I would want the doctor to take quick, decisive, fairly aggressive action. Once this is over, then you can go back to being happy that you have a dog that is older but still healthy and happy. That is the important thing. Get it done, whatever needs to be done.
It is good to hear from an owner who is willing and able to obtain whatever care is necessary for a beloved pet. It sounds like you and the doctor are both keeping a close eye on the situation. I love reading posts like this, as opposed to the posts from people who have waited too long to help the dog.
Good luck. I almost want to say, who among us doesn't reach an advanced age without losing a few body parts, hear and there? I know I've left my share of various tissues along the way, and I'm still kicking.