My dad went into intensive care with Pneumonia?

My dad went into ICU nearly 30 days ago with Pneumonia. He is 75, and is also on kidney dialysis. Each day he was doing slightly better but as he had been in for 2 weeks, they decided to a tracheostomy to try and ween him off the ventilator. A few days after the trac, he started doing quite well and was staying off the vent for 5-6 hours and then even 24 hours and was doing well for over a week. Nurses kept saying he will be on the ward soon and were really positive. Then nearly a week ago something happened and they told us he had a cardiac event and that his heart has been damaged by this and after a scan it shows the heart has expanded and not pumping blood as effciently. When we went to see him he is wide awake and can understand us as he will nodd yes or no and also move his hands and legs and the docs dunno why he is so wide awake but at the same time they said its very slim chance that he is gonna make it and if he has another deterioration then they are kinda telling us that they wont do anything else. We noticed blood coming out of his trach tube as its blood from his lungs and maybe back flow from the heart. Is a real shock to us as he was doing so well. They have done a chest drain and there is no more blood coming from trach tube, is this a good sign? Does anyone think there is any hope even though the docs say no? Even the nurses treat us differently and feels like they have given up on dad.Can all we pray for is a miracle? Is there anything else docs can try? Can he not live with some heart damage? We dont have the heart to say turn off his machine and he is still alive and understands us! Can the docs turn machines off without our authority? Isn't this unethical?