My Father Is 78 Yes Old, Where Do I Start

My father is 78 yes old, where do I start from his medical condition. Last July, he had a mild stroke that hospitalized him for a week. While he was in the hospital he had developed liquid in his lungs that they had him on oxygen because he was having a hard time breathing on his own. His medical condition has got to be more serious being that he had a stroke last year, they had put 3-4 stints in his left side of the back of his neck and they did this because he wasn't getting enough oxygen and blood flow to pass thru his brain or body. He also has vertigo which I wasn't familiar with. Now that he's done that, the Dr told my family that my father really needs triple bypass surgery but he doesn't want to do it because my father's at high risk of not coming out of it and being that my father has a lot of build up in his arteries and in the back of his heart. He also said my father was looking at 1-2 yrs of living. While my father was in the hospital another Dr came in and diagnosed him with a slight stage of Alzheimer's. Well now that its going on to 2 yes in july , my father is doing worst. He's refusing to take some meds and now he is barely eating anything we feed him. He is also more mean and rude with us. Is this the Alzheimer's? My father has always been a rude and mean guy but its gotten worst. He also says the food taste like dirt and at times he can't taste it, is that the meds?