I agree 100% on the diet side of things here he must be doing somthing wrong in order to not have dropped any weight what so ever but on the flip side In order to build muscle you have to eat food so if he's consuming the right amount of protein for his body weight and working out then im sure he's gonna add size, weight, muscle even if if thats not the goal.
Those Kenyans dont have huge muscles due to the way they train for this specific sport.
Footballers run as do sprinters and they seem to always sport a decent pair of wheels, But all of this aside in order to drop weight, drop your calories not too drastically or you could do more damage than good let us see your diet and stats.
Try a caffine supplement in the morning before your jog (on an empty stomach)
then have your breakfast 20-30mins later. see if that has any positive effect.