You can definitely lose fat without doing cardio. I think adding cardio to help lose fat is good for general health. To lose fat you must be in a caloric deficit and wether you get there by eating less or burning more calories off (aka cardio) it doesn't make much difference as far as just fat loss is concerned.

I do believe though that if you can eat slightly more and do some cardio to bring your caloric level down into the deficit you have a better chance of maintaining your muscle mass since your protein intake can be higher etc.

And his beer belly is no different than it was after the first day. Abs/obliques don't grow very much at all. He is likely just feeling sore so he is more aware of whats going on there now.

IW