I understand this is a conditional sentence in the past. 'Might have been' and 'had it not been for the drinking' show that. I have read it a few days but still I don't understand the meaning: Did they shake hands, have a word, did the acquaintance drink?
Even so, our acquaintance might have been no more than a hand-grip and a word—he was a laconic old fellow—had it not been for the drinking. Did they shake hands, have a word, did the acquaintance drink?-- We do not know whether they actually shook hands and had a word, but we do know that they did more: they formed an acquaintance because of the drinking. Whose drinking is