Hi Irishgurl,
Hope today is better now that you have shared the problem a bit with us.
You might cancel your trip and stay home.
Your mother who is very sick right now, might see this as a way out.
She might think, "Irishgurl is not going to leave me, so I can continue this".
She has a good chance of getting all sobered up long enough to see the madness of her actions. By staying home, you are enabling her.
The secrecy of Irish households has crippled many a family.
It is starting to get better, but continues.
I can guarantee you, that in your immediate circle of friends, there are others going through similar heartache. Try Alanon, for some face to face support. It is about those affected by another's alcoholism. Do not leave embarrassment and secrecy prevent you from getting help.
You can go to Australia and keep in touch with your dad by phone and skype.