I would just worry about how dirty little kids can get. I wouldn't want to have to wash them every day because they get so filthy playing outside. At our ages, we can play outside, but don't get nearly as dirty. We don't need a bath everyday. We don't get mud and dirt in places we didn't know we had anymore.
I would carefully explain the process. He might like them now, but in a few month, might get tired of them. It's the nature of kids to change their minds when they get a new idea. Hopefully he will be able to stick with them, but don't besurprised if he changes he mind. He might not like the itchy phases that we all go through. He might not be able to control playing with them and end up slowing down the process.
I don't want to try todissuade you. I just want to get my opinion out there, and help you make an informed decision. I personally wouldn't let my kids hair lock up until they, themselves, stopped combing and brushing.