When sickness plagues the youngest heirs of Durin, Thorin steps in to help his sister.
Post Battle of the Five Armies. The line of Durin finds peace after death.
When Dis's husband is killed in battle defending Thorin, the royal dwarf is burdened with guilt. He steps in to help his sister raise her young son, Fili.
Thorin promises his sister that he will help her with his nephews. One-shot
Thorin made a promise to Kili.