Realistic Plot - Arguments

I have to say that I really loved this movie and, reading some of your comments, I try to argue in favor of the credibility of the movie.
I had the same tendency saying "what the heck, couldn't the parents tell her the truth?", but I found some good reasons why they didn't tell Lili the reality.

1. Remember that in the hospital it was said that she stopped eating because she wanted to die, thinking that her brother was dead, so the parents had known that before how she was - reason to avoid giving her the news.

2. In the hospital, the doctor kept asking what was wrong with her, that there was something else. Well, here comes the whole mystery, remember that it's not a Hollywood movie, they are not explicit at all. What does the song say? It starts like this: "Lili,take another walk out of your FAKE WORLD/ please put all the DRUGS out of your hand/ you'll see that you can breath without not back up/ some much stuff you got to understand " And then, why was she sent on "vacation" to Spain? So, I think that it's highly probable that she had an addiction problem. So that's why her parents avoided to tell her the truth. They had lost one son, they just tried to kept the other one alive.

Now, of course they thought that she would found out the truth one day, but how was she when she found out, in the same state of mind? No! She had a support, she found love in Thomas, she was not so weak, she was seeing her family and especially her father with other eyes, she saw everything through love.

So, I think that the movie wants to suggest that some things are to be said and made in the right moment, it's no use to say the truth just to be "honest", we should balance the consequences before we say something. Just to "throw the news" liberates you of a burden, but that is good for you, without thinking about the one that receives it. :)