| Honestly, If you want a 6pack just do this.
Eat more, good foods, it sounds as if losing weight would do bugger all.
Do core strength work, and ab exercises. Maybe start lifting, or just do pullups, pushups etc.
Run, that would get you fitter if nothing else.
So basically what I am outlining is you getting in shape, gaining some lean muscle, and eventually your abs should start shaping through.
RE your friend. I'm a bit like that, however it's the exercise he does. And swimming keeps you fit and lean. So if he has the body, and does the exercise he should keep in shape even if he eats ****. Don't worry about other people though. | 
