He didn't follow "the letter" of the diet. Atkins clearly states in DANDR that there is a small amount of Carbs in Oysters, Clams, and such.

Amount Per 403 oyster, NFS, raw
Calories 3,836.6
Calories from Fat 1,249.1

Total Fat 138.79g
Saturated Fat 43.56g
Polyunsaturated Fat 54.61g
Monounsaturated Fat 17.72g
Cholesterol 2,990.3mg
Sodium 11,905mg
Potassium 8,801.5mg
Total Carbohydrate 220.6g
Dietary Fiber 0g
Protein 397.76g
Alcohol 0g

Vitamin A 113 %
Vitamin C 348 %
Calcium 254 %
Iron 2088 %
Vitamin D 4,514 %
Vitamin E 107 %
Thiamin 282 %
Riboflavin 268 %
Niacin 389 %
Folate 141 %
Vitamin B-6 175 %
Vitamin B-12 18,299 %
Phosphorus 762 %
Magnesium 663 %
Zinc 34,157 %
Copper 12,559 %

At least he got enough Vitamins and Minerals for the next 10 years. But, it is nice to see that at least one person within a 50 mile radius is doing Atkins...albeit, not properly.