Clearly you aren't a lawyer.
You can't get arrested for theft with no theft has occured. But keep trying.
The only legal question is whether he was in rightful possession, which he was. There is no law mandating that anyone keep their pills in a pharmacy bottle. If he kept them in a little plastic pill pouch would you have then sentenced him to the death penalty lol.
The only legal obligation he need meet is having them issued by a licensed physician. By your logic anyone given medication directly by their physician, which happens every day, should be arrested for drug felony charges.
Once again you let your agenda decide your conclusions.