Non drinker

During a conversation with my brother I mentioned that I don't drink anything more exciting than coffee. "oh" he says "are you still not drinking?"
"no I don't drink anymore".
OVER EIGHT MONTHS SOBER.
He the says "well I was trying to think if I could pick you up for 'our sisters' birthday do"
"why would I need picking up?" I ask.
'so you can have a drink" he replies.
"But I don't drink.....I won't be smoking either" I say sarcastically.
"yes I know you don't smoke" he says.
"well I don't drink either so why would I have a drink?"

Each time I have to explain the rules of 'not drinking alcohol' i am freshly dumbfounded by how some people think that 'not drinking' involves drinking. I mean the clue is in the title.
It's no wonder affairs happen if people think that special occasions are outside of any rules.
Shouldn't it follow that peole who drink should forego it on special occasions?

Im amazed by this thinking and how they don't get it.

I don't drink.
If I drank,
I wouldn't be a non drinker anymore.
NON drinker......you see?