I would not suggest forcing anyone to stop drinking because it is not possible to do so - people in prison manage to drink (albeit some shocking stuff) so I'm sure this man would find it a doddle unless he himself is convinced of the need to do so.
FWIW my gut feeling is that, based purely on what the OP says, with a bit of reading between the lines, this man does have a problem with drink and the quantities are considerably greater than a couple of beers.
Sadly, there is very little "expert advice" available on drink problems (as opposed to the effects of heavy drinking, where advice is freely available but routinely ignored by the people who need to hear it.)
Most people who cannot cut down end up ignoring the warning signs and returning to previous levels of drinking - this is what the OP appears to be worrying about.
Others stop on their own resources or using chemicals such as Antabuse. They tend to be miserable and vulnerable to relapse.
Some people manage via counselling or hypnosis performed by professionals with no personal experience of addiction.
However, I would suggest that the majority of people who get better feel the need to seek counsellors or mentors who have "been there, done that" - peer example is very powerful in such situations.
The majority of such counsellors have recovered in AA or in an AA-based treatment centre (eg the Priory). Indeed, in many such centres, attendance at AA is compulsory as part of the treatment.
All authorities are in agreement that problem drinking is as much (if not more) a mental problem as a physical one so, certainly, some form of counselling would seem to be essential - IF (and only the OP can answer this) the man in question is unable to stop or control it alone.