If your son has the dive and motivation, online classes allow you to do the classes at your time and pace. Freeing up the rest of his time to REALLY get going on making money in life.
As for missing HS graduation? Meh, no big loss. It’s a bigger deal for parents than it is the student.
After 22 years of school, and multiple graduation ceremonies for various levels of education, there was only one ceremony that I had any feeling for. If that ceremony did not happen it was not going to be the end of the world for me.