two of them are not like the others...

Last year I read an incredible fanfic where Bilbo finds kid (and traumatised) Fíli and Kíli and ends up taking care of them. It's a monster of a story, and unfortunately unfinished, but the characters were all so well written that I couldn't resist.

The story can be found by the title of The Winter of Discontent by Brass_Brassicas on Ao3