I think you did a very noble thing. You saw it right through to the end, knowing how much it meant to your partner. And saying that you wouldn't let it be the case all the time when the dust settled. That boy will be so grateful for your help. You didn't judge him for his habit either. Now I know many in his boots would have robbed you blind the minute you turned your back as addicts, are fixated on one thing. So, yeah it is risky.
I never managed to convince my ex that "junkies" are people with real emotional troubles. He would admonish my mum in the pub for speaking to ex "junkies." My parents were never black and white, but i'm slowly trying to see things their way for some things. My ex's cousin died from heroin and he spoke of him like he was the devil incarnate.
But of course my doctors have me saddled with the, tends to "abuse alcohol" when not doing well.
I was never a good friend. I wish I had bonds with a friend like that. I know there's a line.
I had a pair of friends where one was the others lap dog. I vowed not to be taken advantage like that, so my female friendships all dissolved.