Bereavement is really shattering and having a drink (or two, or three) does seem an easy temporarily way of blotting out the pain. But long term it doesn't help and only the passing of time will help your grief fade, so if you can try to find some other activity to to indulge in when you feel the temptation for a drink coming on I think it will help you physically. Can you experiment and try to find some non-alcohol drink you enjoy? Possibly something with a bit of fizz like tonic and orange juice, or even some kind of healthy drink like chilled tomato juice or V8 vegetable juice?
If you can imagine your mother talking to you now, what would she be saying to you about your heavy drinking. Just because you don't have her physical presence with you, try not to ignore the loving legacy she has left you. Your best way of honouring her memory is to know that she would be proud of your efforts to cope with getting on with your life without ruining it by alcohol. It IS hard, but take a day at a time and try to get some professional help if you feel it really is taking over your life to the extent when you are beginning to destroy yourself.