This has nothing to do with architecture.  A drafting tech may never work for an architect, and probably won't if its a specialized mechanical engineering degree.  Drafting standards are very different based on what kind of drafting you're doing - mechanical, architectural, civil, electrical, etc.  Not just that, but schools don't really make you good a good draftsperson.  99% of his real world skill will come from experience picked up in offices during internships, etc.  The basics will come from school.

Except for someone with life experience relevant to mechanical drafting no one here can give you any informed advice above anyone else.

I would highly suggest taking any sort of drafting or design class in high school before making the choice to study architecture in college. At best, it will prepare your son for the stress and demands of a design course. At the very least, he'll learn how to draw, and if he decides to study archiecture or engineering in college, he'll be at an advantage. I went to school with people who didn't know how to use a scale or how to and draft. I knew that already because I took classes in high school.  I actually ended up showing a lot of people how to use the drafting tools and later on CAD.

there's a big difference between what an engineer might have to draw and what an architect might have to draw, so its hard to address the questions of someone who might want to be one or the other.

as a teacher, there's nothing worse than seeing the 'architecture' drawings someone did in high school and having to shrug your shoulders and explain all the reasons why they are not very good drawings, even though whats on the page looks like what everyone thinks a house looks like. From what I've seen, local vocational type programs are more interested in producing students who are 'certified' in the use of a specific cad program - which in no way means that they know how to draft. By drafting I mean that they know how to collapse 3 dimensions onto a flat page and how to flip around and intersect and cut that information. Knowing how to do these things becomes less critical when the software can do it all for you, so I'm even more suspicious of someone learning how to 'draft' when taking what is essentially a vocational software training class. Is your local program better? How can we tell? Its pretty doubtful such a program is a place to get any design experience or to get a sense of the stress/demands of college courses - unless its a really good program. I also dont believe that work experience will teach someone how to draft, but it will teach them what needs to get drawn for different sets and situations - thats not drafting though - in my opinion.

to happily cut myself short here, i would say that the sooner and better acquainted someone gets with software, thats all for the better. and the sooner one might be able to differentiate between their desire to be an architect or engineer, thats also for the better. But im very suspicious of any high school design action and equally suspicous of any high school drafting experience - but thats just from the messes I've seen. So yes, the sooner the better, the more to build upon the better, but there is a real qualitative difference between software training and being trained into a discipline.

For Pete's sake, people, the man is asking about a drafting program in high school.

Yes, your son would greatly benefit from this kind of exposure to drawing and learning spatial relationships at this early stage.  (Some of the well-intended comments above rightly point out that such a program is not architectural; very true.  And if the choice is between an architecture curriculum and one in mechanical engineering, then by all means choose the architectural one.  But most high schools don't have this choice, and a good program in an allied field --one that trains youngsters in space, precision, drawing, etcetera-- could be very beneficial.)

My recommendation would align with my colleagues above if the student in question were applying at the college level, but he's not.  He's what, 14?  This is a great opportunity for him to start learning some (not all, but some) of the basic skills needed in architectural training.  To this, he might take whatever opportunities available to learn architectural software / techniques.  Also, visiting local architects' offices and talking to practicitioners is another good way to learn more about the field.

Good luck.