When did his mother die exactly? (spoilers)

Just before he leaves on his trip, you see the guy visiting his mother. She gives him the dreaming/sleeping ballerina and predicts that he won't return. Then, when the accident happens, you see that his mother actually died and that the coffin is burned with him as the only one there to say goodbye.
I don't get it - is this a flash back? Is this all a metaphore (again fire, like in the castle)? You see by the way the car rolling down the hill, and in the next scene it is right next to the road... Did he hallucinate? I had the impression the mother died by "feeling" the accident, but then again: he couldn't return at that moment to burry her.