Note under "Time Controls" that his timebank is depleting. How much timebank he has left is something you don't know for sure, but you might get an estimate by adding up when you last moved + 3 days normal move time + however long it has been since then. Easier is to look for a "trash can" icon in your game list since this game just started and the game will be deleted as if it never started. Otherwise look for the "skull" icon which indicates ALL his available time has expired, click it and the win is yours.