My (28m) uncle (56m) is upset with my reaction to my abusive mother dying. He doesn't know about the abuse and I don't want to tell him

My mother (50f) died a couple days ago and I honestly don't really care. She was abusive and cruel throughout my childhood. It really ****ed me up for a while but I spent years getting my act together and realized that dwelling on the past only hurts me. I have a good life now and I'm happy
As an adult I've grown close to my uncle. When I was a kid I thought he knew about the abuse which cause all kinds of issues between us but now I know he had no idea and he's a really sweet (and naive) man. He knows my mother and I weren't close but I never told him why. He's convinced she was just his annoying, free spirited, trouble maker sister and he loved her. I don't see any reason to take this away from him especially now that she's dead.
He asked me to come to town for the funeral which I agreed to because I know it means a lot to him. I took a week off work to go out and visit him and attend. Last night we were sitting around drinking and he eventually went to bed leaving his wife and I alone. We don't have the best history but we try to be civil around each other. I know she was trying to be nice but she kept talking about how hard this must be for me and how hard it is to lose a mother and trying to get me to open up and I was drunk and tired and I just snapped. She said something like "you look like you're not even upset" and I said I'm ****ing not and I could not give less of a ****. Then I just went to bed because I didn't want to deal with it anymore.
I know I ****ed up but she's blowing it way out of proportion saying I must be a heartless psycho for not caring that my mother died and she's got my uncle all upset because he doesn't understand why I would say something like that and I just don't know what to say. At this point I just want to go home
TLDR: I don't care that my abusive mother is dead but don't know how to explain that without bringing up the abuse


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