In the back of my mind, I’ve wondered if both Anna and Daniel were injected with some kind of poison that goes undetectable on autopsy. That would mean the drugs were a red herring.
What if Daniel took some ambien to sleep, then when he was just sleep, H. got up to inject him.
What if he then stuffed a bunch of drugs down his mouth, which would be considered the cause of death.
What if Dr E. was able to supply the injectable, non-detected poison to him? Maybe keeping Anna depressed and drugged for several months was the part of the plan.
Maybe the dirty needles that were used on Anna were given on purpose to add to the muddy picture...If you really think about it, Anna died with so much going on in her body, no one would think of the unnamed poison (used by the Russian secret police on umbrella tips to kill people).
Remember that Chloral Hydrate is rarely tested for. Since Daniel died BEFORE we had any knowledge of that drug, I’d ask that he be tested for Chloral Hydrate.