If you talk with him, you will have the option to either buy a drink, hear a story, or hear some gossip about various things. You can ask him about Canifis, about Morytania, about some of the shopkeepers, or about Paterdomus. From this you can discover many things, such as the average age of werewolves (Roavar is over 400 and he is not considered an "old" werewolf), and that werewolves like serving Lord Drakan, unlike much of the populace. If you right-click him, then select Trade, he takes 5 coins from you and gives you moonlight mead, an alcoholic beverage.