ok back here again because these two excerpts are soooo interesting to look at together. brienne and catelyn's relationship is really deeply important to both of their characters, despite the relatively brief amount of time they spend together on-page, and imo its significance to the story doesn't end with catelyn's death.
in the yellow highlights, catelyn and brienne bring up the notion of doing things for the living vs. doing things for the dead (there's also a lot going on thematically in the green, but that's for another post lol). this question is extremely prominent in catelyn's chapters, especially as we see the way she is changed by grief. in earlier parts of acok, she brushes off offers of revenge for ned's death:
she also makes a similar argument to brienne to stop her from essentially throwing her own life away to kill stannis on renly's behalf. (sidenote: knowing how brienne ends up in the last published chapters wrt lady stoneheart and jaime (living as of yet, unlike renly), and the general difference between brienne's feelings for renly vs jaime, this is something i'm personally really interested to see play out).
as the books progress however, the intense amount of loss and grief catelyn experiences throughout changes her view on this: after hearing about bran and rickon's alleged deaths, we see her savoring roose bolton's gift of theon's flayed skin, when just a book previously she was thinking of how seeing the lannister's heads would change nothing for her (after ned's death). and of course, this culminates in her final chapter after she witnesses robb's death and kills jinglebell, an innocent, with her own hands.
but while as readers we saw this evolution (devolution?) from catelyn's pov, we also have to remember that this isn't the cat that brienne knew. throughout asos brienne also experiences a lot of character development, but even so continues to think of the version of cat that she left at the end of acok, still acting on behalf of her wishes.
therefore i am so, so interested to see how this theme plays out for brienne (i haven't finished affc yet lol) because i think there's definitely something going on here with her competing allegiances: to the catelyn of her memories vs. lady stoneheart vs. to her living daughter(s but brienne thinks arya is dead) vs. her relationship to jaime vs. hers to the people of the riverlands/protecting the innocents who are casualties of their lords' actions. she's a character so defined by her idealism and desire to do the right thing -- though she often struggles to determine what the right thing is -- in a way that catelyn, who is quite jaded and tends to prioritize family and close personal ties, is not. and now that catelyn (or something close enough to her, at least in brienne's eyes) is walking around having been reduced to her desire for revenge, brienne is going to have to confront these theoretical questions about duty to the living and the dead in a very, very literal physical way.