Ill give my 2 cents-
If his ambition is to run a small business with just himself and a helper or two then i would say go to school. Small businesses like this are just like a job. If hes not there then there is no money coming in.
I never realized this until I was working with just 1 helper and had back problems. If I was not able to continue then the business that I had built up over the last few years would go down the drain and my customers would find someone else to service them. That was a wake up call! I now have up to 11 guys in the peak of summer and dont lift a finger other than a pen and clipboard!
If his ambition is to build up the business so he has several employees doing the work and he can manage the business then I would say go for it. This could take several years to get to this point but you need goals to hit.