An increase in muscularity can be perceived as having a larger build but as far as I am aware, body frame in terms of actual bone mass and size cannot be changed through resistance exercise nor deep breathing - if this were true then endurance athletes who breathe deeply routinely would be gigantic. For the muscularity, he would benefit from exercises which target the specific areas he wishes to work on performed within the rep range of 8-10 for 3 sets which appears to generally be the most optimal for hypertrophy.
Exactly. For bulking the ideal reps are 8 and 10-12 for some small muscles like deltoids. Never more.
With 30 reps you'll gain only stamina but you'll look skinnier. Of course they won't help to look bulkier.
And to be ontopic, I think that clavicle lengthening is a stupid idea. Most men with hard wotk out can become at least average built so even if they have small bone structure they could be look ok with hitting the gym.
After all not many people, even the tall ones, have a wide back so there is no need to have this aim. Of course being tall and muscular is better than simply tall but still it is not so important and it is really a bad idea to do clavicle lengthening because you'll still have a skinny body with big clavicles.
Completely ridiculous imo.