What makes a sober person act drunk?

I have seen this person drunk and sober. He doesn't drink often. When he does drink, he leans to the side, rolls his head when he speaks, speaks very slowly, and advocates violence (doesn't commit violence just talks about it). He also staggers and has no coordination. A few times I have seen him speak as though he's drunk. On these occasions I knew he had nothing to drink, his coordination was still good. Could this be a symptom of a mini-stroke?