Oxycodone is not a form of heroin, and neither is methadone.
Methadone is used to give heroin addicts the same feeling as heroin, and the feeling goes away after the first use.
Oxycodone is a pain reliever that is one molecule away from being heroin.
At least he's not doing Heroin.
I've done Oxycodone, and methadone. it's not bad, as in it's not that addicting or fun.
If you pm me ill gladly explain to you what to do, and to help.