I was about to say I really hope you're not trolling. But - I guess I hope you are trolling - since it would mean it's not true. But it's obviously incredibly poor taste if you are, because a lot of us here, especially on Other Drugs - and specifically opioid/opiate users, we've almost all lost people(s) close to ourselves. It's incredibly tough to go through, because on top of the death, as if that weren't enough - there's so much stigma and taboo. It's really tragic that so many people who tragically lose their life this way, they can be "written off" as "just another junky" but that just isn't the case, people - all of us, people - we're more than that. Our addictions DO NOT define us.
Anyway- assuming you are being truthful, then I'm incredibly sorry for your loss. As I alluded to, I've been through some losses myself along these lines. Any loss is devestating.
Regarding your specific question, I'm quite sure no one can really answer it. But my best guess is it would depend on whether he survived for a while and died in hospital, or whether he died within a few hours.
Because if he died quickly (say within 8 hours of taking the over-dose of pills) - then in all likelihood I would say he went very peacefully in his sleep. I'd say the combination of opioids and benzos would have had him gently fall alseep and then his breathing would have stopped, leading eventually to a cardiac-arrest.
Unfortunately - if he survived long enough to be in hospital in an induced coma or even conscious - especially if it were for days - then the death *may* have been a result of APAP damage to his liver. The amount of APAP (think common OTC pain killers, like Panadol in Australia) in 25 Vicodin is unfortunately enough to cause acute liver damage. If he died of liver failure, then that would indeed be a painful death.
But I would say the far more likely situation is that he probably died relatively peacefully and 'pain-free' in his sleep.
But no one can really tell you. Wait for the coroners report and read that. In my personal experience, a coroners report is extremely 'cold', not emotional at all - a purely scientific and empirical detail of all the factors leading to his death. They can be difficult to read, as they're certainly NOT written to console the grieving. But they do tend to give you a very precise account of the death.