AITA for having narcotic pain meds in my medicine cabinet?

Throwaway because I'm gonna reveal some medical info and some IRL people know my main account.Wife had a C Section about 3 months ago. She was prescribed Norco (Hydrocodone) for the pain. We filled the prescription (20 pills) and then she never took it. She used Motrin and Tylenol only. The pill bottle went into the medicine cabinet in the bathroom where we forgot about it.Fast forward to Christmas Day. We don't want to take an infant around to all our families gatherings in flu season, so we stayed home and invited anyone over who wanted to stop by during the day.My wife's sister (so my SIL) Jane and her boyfriend Bob came by. Jane and Bob have been dating for a few months. I never met the guy before. My wife met him once. My point is that I don't know this dude from Adam, but he seemed like a nice guy. They stayed for a while, played with the baby, exchanged some presents, and we all had a good time before they left to go to their next stop.A few days later, Jane calls my wife irate and screaming. Bob stole the Norco. He is apparently a recovering addict who has been clean less than a year. We obviously didn't know this. He has now vanished. His work hasn't heard from him, his parents haven't heard from him, and Jane hasn't heard from him. He could be on a bender or dead for all we know. Jane went to his apartment when he wasn't responding to her and that's when she found the empty pill bottle with my wife's name on it and called us screaming.SIL blames us and is beyond pissed, which I can understand. She needs an outlet for her anger. What I don't understand is about half the family blames us too. They understand we didn't know about Bob's addiction history, but they said having unused narcotic medication just sitting around is irresponsible and we created this problem. It's causing a bit of a rift between the people blaming us and those not blaming us, and we (and my mother and father-in law) are caught in the middle because SIL has been on a rampage against us for "destroying her life."I'm trying to be empathetic to Bob and SIL, but I don't agree. First, we legitimately forgot about it. Neither of us take medication regularly, and we had a newborn to deal with, so we weren't thinking about a bottle of pills in the corner of the medicine cabinet. Second, Bob didn't know the pills were unused. We don't know him and he doesn't know us. For all he knew, my wife could have a chronic condition and need those pills. It's not like he would recognize the prescribing doctor's name is an obstetrician. Am I not allowed to have medicine in my own house on the off chance that a recovering addict will come by and see it?I think Bob is firmly the asshole here and my wife and I don't have any responsibility. If we had known he was an addict and still left the pills out, then maybe, but we didn't know.But, I don't have any experience with addiction or even taking narcotic pain meds, so maybe I am the asshole for not being more diligent about getting rid of the pills.AITA?EDIT: Thanks all.I'm glad my initial reaction wasn't off base. For those asking how anyone could blame us, scroll down to the ESH verdicts because a few posters have nailed the exact things some of the family is saying. Not so much that it's our fault Bob stole the pills, but that we are "part of the problem" that has allowed the opioid crises by not securing or disposing of the pills. via /r/AmItheAsshole https://ift.tt/2FvHOt8