Darn, his first sewing and it's way past my own already. His corners match up well and he should do much more sewing now that he has it under control.
As in construction, he learned how to measure twice and cut once.
Now take him to the LQS and let him pick out some manly fabrics, and remind him how cold the coming winter is going to be. Quilts will be needed, lots of quilts, even in California.