dbh,
I could see myself getting trapped like that too, and I am an alcoholic!
An elderly woman with dementia? I have no ideas, other than setting a boundary with her.
"I will not support your addiction by taking you to get booze or giving you money."?
It's okay dbh, we all did and/or do things that we wish we could take back.
Maybe practice saying no. I had to practice, and I had to learn to keep out extra stuff, like explaining why I am saying no. No need for that. NO is a complete sentence.
Beth