Of course you feel sad! You have compassion, you have feelings.
I have a relative. the current political climate has made her -- well something. I don't want to veer into diagnosing her, because I'm not in that business. But -- she's taken to vilifying people who voted differently from her and threatening to un-friend them: people who have been her friends for decades. *I* remember the girl who hemmed one of her own dresses shorter in an afternoon because her classmate at graduation had alcoholic parents who never took her shopping for a floor-length dress for class night. That's what I want to remember . You post made me wonder if booze is an issue with her. I don't know. I love her - I don't want to create a lot of drama unfriending a relative, so I've stopped following her. I voted the way her ex-friends did - so that topic's off the table. I'm tired or her tirades and the hate makes me sad.
This is a long way of saying there may be a constellation of issues here, Alcohol may exacerbate a problem, but may not be the only problem. People are complicated.