I am so sorry to hear of the difficulty you are having now following the loss of your parents. I think there are quite a few people who experience a delayed grief or a returning sense of grief. I don't think the sadness of any loss ever fully leaves you. How can it when the love you have for those you have lost does not disappear? Many here say grief is like a roller-coaster; there are bad times and better times and it does seem to stay that way, no matter how long ago the loss occurred. I came here after losing my mum in 2017 and really struggling with that, but I lost my dad in 1985. Some might say that was a long time ago and you should be 'over it' by now, but I don't think you do ever really get over such a close loss. You learn to live with it. The initial pain does dull, but it never really goes away. There are still times when I miss them both so much, well, most days if I'm honest. I certainly think of them both every day and still talk to their pictures and I don't think that is so unusual either. Grief and loss change you as a person and that's something you have to learn to accept and adjust to also.
For myself, I found that moving on from a loss is something you have to find ways to help yourself do and help yourself cope with on an on-going basis. Alcohol won't help, I'm afraid. It just makes you more depressed after a while, even if there is an initial boost to start with. Talking works much better along with writing about how you felt about those losses and how you feel now. If you go to your GP, they will refer you to a grief counselor, which will help with this and in there are bereavement groups in some areas too that may help you to join. In the absence of those, try writing about it all, not just the losses, but your experience of losing each of your parents both at the time and since then. Try going out for a walk when you feel down. Getting out of the house really helps. I found it really helped to walk in the park and that was a good place to sit and think about it all and try to come to terms with it all. It was a calming and beautiful environment that helped me feel calmer too. You have the proof that drinking didn't help your dad already, so don't go down the same route. It won't help. Look for something better that will help you move forward. Your parents would want better for you so it's up to you to find a way to get through this in a more positive way yourself now that they are not here to help you do that.
Wishing you well.