In a medium-sized saucepan, heat the oil over medium heat and when hot, cook the garlic for about 1 minute or until softened. Take care the garlic does not burn. Add the cabbage to the pan and cook for 2 to 3 minutes, stirring, or until it begins to wilt. Add the beer and cook for about 5 minutes to give the beer time to reduce. Add the chicken stock and simmer for about 20 minutes or until the cabbage is tender and most of the liquid has evaporated. Season to taste with salt and pepper. Cover and set aside to keep warm.