This question is actually regarding my son, who I teach - or "guide" rather, he kind of teaches himself. He cannot reach an octave but has been wanting to learn Mozart's Rondo Alla Turca, and I'm not sure how to advise him. First, I will suggest that he learn the sections without octaves and focus on perfecting those for a while. Hopefully, he will have a growth spurt soon.

But when it comes time to learn the octave sections, should he stretch as best he can and play them anyway, even if it is messy? Or should he roll them? Just wondering what other teachers do, because I have not encountered this yet. My other students are not this far in repertoire, but still the other ones this age can already play octaves anyway.
By the way, when can a boy typically reach an octave? How common or uncommon is it that he is turning 12 this month and still cannot reach?