It may be a problem - possibly not doing the liver a lot of good, for example. But not necessarily an addiction though. Could be his choice to drink three glasses a day because that's what he likes doing - not an addiction.
Smug
adjective: smug; comparative adjective: smugger; superlative adjective: smuggest
having or showing an excessive pride in oneself or one's achievements.
synonyms: self-satisfied, complacent, self-congratulatory, superior, puffed up, pleased with oneself, self-approving