If any of them were awake, do you think the friends statements will be published?
I think toxicology would go a long way toward explaining it but I bet it never gets done.
The media reported that an autopsy will be done, and that will certainly include toxicology. However, Dutch privacy laws are very strict, and I highly doubt we will anything more of this case from the police. The friends themselves may speak out at some point, they are free to do so, of course.
I just hope that the fact that this was most likely an accident and not self-harm gives the family some peace in their time of mourning.