Dear Smitha,
You can stop him without his knowledge by using some ANTICRAVING DRUGS. But the problem is if you use this it will seriously affect him if he still try to drink, this is the main mechanism of this anti craving agent. However best way is just counsell him and make him go to a doctor, then he can be treated with several drugs which will prevent any withdrawl symptom as well as counseling which will help him to resist the desire. Just wait for the proper time to convince him.

Hello Taslima,
If you are thinking to stop drinking habit of your husband without his knowledge, then even if you become successful with the help of drugs, that will be only temporary.
Also such drugs carry many serious side effects. Still use of a few drugs is necessary to minimize withdrawal symptoms which should be taken under medical supervision.
If your husband has developed physical & mental dependance then abrupt stoppage of the alcohol without administering proper drugs would have adverse effect on his health.
Best is talk to your husband on this subject with care & affection, gaining his confidence. If you are successful in making him ready to visit any consultant regarding this,then you will cross half distance towards your goal.
Always be positive even with your husband, Instead of talking more on bad effects of alcohol, make him to know about best aspect of life if he throws that habit.
Make him believe that he can stop drinks with some efforts to get better life style, make him busy in constructive works in free times.

Take care