I do not own the hobbit. This is set just before the company leave Erid Luin, actually focus's more on Dís..
When Thorin comes home looking more alive than he has in years, Dís can't help by smile, that is, until her brother starts mentioning swallows flying towards the mountain, and the signs. Then, her heart drops and she feels like someone has sucked out her insides.
Dís loves her brother, more than anything bar her sons, and she'd do almost anything to make him happy. But she knows deep in her heart that if her sons join her brother and go on the quest to reclaim a home that neither of the older Durin's folk can truly remember their farewells will be the last time she looks upon them in life.
The boys are beyond excited when Thorin mentions it, they're young and naïve to the true horrors of war, and the glory of their quest illusions them to the hardships and the very possible reality that one or all of them may not make it there alive. Their desire to make Thorin, the only father figure they've ever really had, happy overrides all her pleas for them to reconsider, or for Thorin to hold off the quest until her boys are older, until she's had a few more years with them, but his mind is set.
The following days are a whirlwind of colour and sound and packing and amidst it all, Dís, daughter of Thráín feels like she's watching it all through a smoke screen, the boys sharpening weapons and packing provisions aren't her son, the man who spends hours upon hours Mahal knows where, that's not her brother.
She can't let herself think of them as hers, because if she does, she'll cling to them and never let go. Her mother, father, grandfather, brother and husband, all gone, and now, she's going to lose her boys and her remaining brother, this isn't fair. But she is a princess of Erebor, and the lessons on decorum and control drummed into her head as a dwarfling serve her well.
The day before they're due to leave, Balin, pulls her to one side and embraces her with all the love and compassion her father never held and in that moment, she is not a princess, she is a woman, a mother and a sister, her tears come thick and fast, breath coming in short ragged pants as she sobs into the chest of the person who taught her how to swing a sword when her brothers deemed it too dangerous, cries for a lost childhood, for kin lost and leaving.
The next day, when they're gathered at the gates of Erid Luin, she tries to hide her fear and her pain, and for the most part it works, but when Kili picks her up and spins her round promising to make her proud, she nearly breaks. Because she'll always be proud of her boys, no matter what and she tells him as much.
And as she watches her remaining family leave, Kili walking backwards so as to wave at her for longer, what's left of an already abused heart, breaks.
It is many months later, that she receives a raven telling her of the death of her sons and her brother. When she arrives at the thrice damned Lonely Mountain, Balin meets her, and she doesn't need to ask, the redness of his eyes and the disarray of his hair tell her everything. She throws herself into his arms and they're lost in their pain.
"I'm so sorry lass" Balin mutters into her hair, his tears soaking the thick dark locks of the dwarf woman's hair.
She can't speak, because that makes it real, and she's not ready to face that reality yet. Because all the time she doesn't voice it, they cannot truly leave her.
If ignorance is bliss, denial is truly Avalon.