Morphine , heroin, opium, oxycontin, vicodin, etc, are all from the opium poppy, differing only in how they're refined and if they're mixed with ibuprofen or acetominophen. Taken everyday, definately addicting.
Most likely he will become an addict. Morphine croses the blood brain barrier just like heroin. How long has he been taking it for? It may be too late already. Morphine in the smallest amount is very addictive. Not a good idea for him.