I feel sorry for your friend, it's horrible to watch a loved one (my pet's are no different to me than other members of my family) like this.
I can't offer any advice on treatment I'm afraid, but personally I think knowing when to say goodbye and let them go peacefully and painlessley rather than extending their suffering or lack of quality of life because we don't want to put them down is the biggest thing for me.
I watched my grandmother die slowly over the period of 5 years or so after a massive stroke (after which the docs said she wouldn't last more than 48hrs). She was simply to fit and strong for it to kill her, and over the first year made quite a good recovery, but her life was pretty miserable for years afterwards as she had lost the ability to walk, or even go to the toilet by herself. She was an extremely active women in her 90's right up to that stroke, and it was heart breaking to watch, mainly because I knew that she hated what had happened to her.
If I could have done anything to help stop her suffering, when we all knew that it was just a slow decline to the end, I would have done it for her, but euthanasia isn't legal for people. I certainly won't let any of my dogs suffer like that.
Just my 2 cents worth.