Factual error: Many of the "western" products used in the film are in packaging from the present day, not from the time the film was set (1989-90). For example, Coca-Cola Light had a white label then, not the silver one in the film. Other examples are Jacobs Krönung coffee and Heinz ketchup, shown in recently redesigned packaging.
Factual error: Alex's mother lies eight weeks in coma. After she wakes up she remains bedridden for weeks (we don't know for how many but that doesn't really matter), first in hospital, then at home. When she sneaks out of bed for the very first time and walks out of the house she does so without any major signs of dizziness - anybody who has spent a few days flat on his back in hospital knows about the difficulties to get vertical again. The problem is not only a mechanical one like weak or stiff legs, something a physiotherapist could help with, but mainly the fact that the heart would not be able to build up enough pressure to supply the brain with sufficient blood. It's absolutely impossible that Christine would be able to get up the way she does after eight weeks not only in bed but in a coma.
Answer: Lara did indeed tell Alex's mother the truth. Realizing how much her son had done for her, she left him with the illusion that she never found out. The audience knows better.
Ioreth