I personally think all engineering students should take on this type of a project. It may not be a money maker for him, but it will certainly highlight the differences between "looking good on paper", and real life manufacturing. As a Mech. Eng. Tech. with several years of machining experience, I have witnessed all array of engineering wonders that looked peachy on paper, but didn't work worth a crap. I fully believe that to be a good Mechanical Engineer, you need real, hands on, manufacturing experience. This level of experience isn't available in a one or two semester, spoon fed course.
Best of luck, it sounds like a great project, that you will learn volumes from.
Later