Mean, nasty, little thoughts

Dear Brooke and Coaches,
Question about how to manage some really mean, nasty thoughts that spring up once in a while. My mom is very ill with COPD yet continues to smoke. I’ve largely managed my mind to show up how I want to (accepting, compassionate, helpful) and I’m very much at peace that this is her journey and she’s living with the consequences of her choices. And I’m living with the consequences of my choices. But especially when I get tired or run down these mean little thoughts creep up like – is that cigarette really worth your life, you expect me to show up and care for you when you don’t care about yourself, etc, resulting in feelings of anger and resentment. I bite my tongue and don’t act on them – although I can get a little snippy and have to go home before I say something I might regret. I’m trying not to judge myself or feel guilty about these thoughts but I do seem to dwell on them a little too long, and tend to stew after a long day with my mom. The same is true for mean little thoughts about my brothers who don’t really show up, expect me to handle things and then text me for news. I try to tell myself to stop it, these thoughts are not serving me or anyone in this situation. But maybe I should be allowing myself to feel anger and resentment? If so, how does that help the situation? Or maybe I haven’t really fully accepted the situation and made peace with my choices? I’m also interested why these thoughts come out late in the day but by morning I seem to be back on track. Advice would be greatly appreciated.