I don't agree with the whole "responsible for Amy's death" because he "gave her heroin" - she was a grown adult and he didn't force it down her. She asked him for it. Like he said, her death was connected to alcohol. I do feel some of the comments thrown at Blake after her death were a bit harsh.
Like I say, I have completely changed my perception on him after the JK interview.
BIB - she was likely high on softer drugs like cannabis when she asked. Ever done something when high or drunk and regretted it?