It sounds as though we have a major thing in common-the Love of our parent who is suffering. I just want you to know that with time, you will develop a sense of strength and courage. I also want you to know that some days are HELL (it's normal) and some days there is light!! Take this ONE DAY AT A TIME. Half of the battle is training yourself to live in the present moment.
I met a man who is a 5+ year survivor of the exact scenario you describe- he is alive and well. I noticed he had a speaking device and because of my exposure to this I approached him. We spoke for an hour and ended up hugging. He is a miracle and I MET HIM. Come here, there are many miracles. I am so SORRY about your pain. I feel it, I know it. It is the worst to see suffering, isn't it?