Analyze the cause of your father's death first. I think this is caused by many reasons:
The first one, I think, is suffocation. When people are drunk, their nerves are paralyzed, and because your father is lying on his back, he can't vomit when he vomits, but he is inhaled into the airway and suffocates.
But according to your description, the way you gave your father CPR was wrong, which would also lead to suffocation.
Second, I think it should be myocardial infarction, heart failure and sudden death.
Third, digestive tract diseases and acute pancreatitis.
I think your father's friend is at fault. They didn't fulfill their obligations, they should have been sent to the hospital or told their families, so that even if they suffocated, they would have three or four minutes of first aid time and wouldn't let the patient die.
However, your father, as an adult, and he knows that there are so many basic diseases, he still drinks. The result will only be tragedy.
People can't come back from the dead, I hope you're sorry!