He is suffering from withdrawal symptoms. Getting rid of any addiction takes a lit of patience ,determination and will power. He will have to be counselled, and can be helped with homoeopathic medicine. A good diet, regular exercise and a good happy professional life alongwith family life and good support of friends and family is required.

I think,  the realization has to happen  within. Perhaps,  he may not be stopping it,  just because  people force him or nag him to do so.

He requires to be assessed by a Psychiatrist to help him abstain from smoking and handle withdrawal. His behavioral problems may be an indication of an underlying problem