I am so very, very sorry, rosa.. There is nothing more tragic than the accidental overdose of a young person with a lot of promise. Last year, the nephew of a good friend of ours--with whom I had had a few really good conversations...really poised, gentle young man--went into NYC to meet friends. His parents were staying at my friend's house, as they were all planning on going to a family picnic the next day.
My son was at our friend's house, when his brother got a 212 call on his cell phone. "Oh! That must be ____ to tell me when to pick him at at the train station."
But it was the NYPD, calling to tell him that his son had died of a heroin OD in the hotel. Totally accidental--he had planned on attending the family picnic the next day. This kid was extremely talented and intelligent. So, so tragic.
So I empathize with you and I share your pain.. It's hard to make sense of it. I wish you and your sister peace in dealing with this loss.