Can prolong Alcohol Abuse cause memory-loss?

My father had a back injury when he was a young man. Every time he is in pain he use to drink a few drinks and that is all now he is drinking even more. He sometimes drinks so much he pes out. I no longer live with him, and I worry about him. He cooked me dinner yesterday and after dinner my husband and I was hanging out when he just ped out. 2 hours later he woke up and didn't understand we were over. When I told him he made dinner he informed me he doesn't cook and when he does cook he burns everything, yet he makes some of the best meals i have ever had. I am wondering if he might have Dementia, or the like... I have a doctor apt for him but it is three weeks away if ya'll can help please.