She goes to stay with her sister, Lea (Elsa Zylberstein), who--huge logic gap--didn't know her nephew was terminally ill (even though he would scream in pain and could barely move until he was fatally injected by his doctor-mom). Once Lea finds out that it was a mercy-killling, all tension and dark clouds vanish. (Why DID she think her sister did it?) What Juliette did was OK.
I was really enjoying this film (hoping my guess was wrong), but I thought it strange that this French movie was filled with children everywhere (I mean, this is France, right?) Well, the nation doth protest too much. When we are cut off from the Source of Life, the ONLY choice left is death. A culture of death. That parades as a culture of life.
"I've Loved You So Long" joins the growing catalogue of euthanasia films (and I shan't be surprised if it wins an award): "Million Dollar Baby," "The Sea Inside," etc.