I am so sorry for your loss . What shocking news to endure along with your other issues. Your head must be spinning and your heart is surely hurting.
From what you have written about your grandmother tells me you have many good memories and found strength from your relationship with her.
Try to be strong like she was and fight the beast of addiction that will at the very least cloud your mind and numb your emotions ..emotions that need to be expressed..just like your grandmother expressed her emotions.
Please resolve to not drink at this tumultuous time.I know it only takes a moment to choose to drink but you will regret this decision.
Take care of yourself and my condolences also to your entire family