When a parent is constantly negative

It’s become a constant thing now, that whenever I see my mom, she throws negativity around especially adult children. Adult kids are assholes, that don’t make time for the parents, don’t do this and don’t do that. She’s got very high expectations but makes hardly any effort herself and throws guilt trips and negative/offensive comments. To avoid arguments I just smile and nod and stay silent. After awhile she’s not that pleasant to be around it makes it all the more difficult. She’s extremely rude and judgmental of my brother’s long term girlfriend, she’s been like that about my husband too, amongst other things. I’m not sure if she lacks complete self awareness that her attitude is toxic and so gloomy. I don’t know how to convey to her that her attitude sucks the good energy. Any tips?