It is reasonable to think he'll pop painkillers, which isn't very good at all with someone that has horrible addiction tendencies. I get it.
No, you obviously don't get it.
To an addict, there's NOTHING more important than your next fix.
And there's nothing reasonable in thinking any addict can just pop painkillers without relapsing. It would be difficult even under strict medical supervision for someone with Steven's history to not relapse.
It's not about kicking someone when they're down. It's the reality of the disease.