OP- doing tech school courses instead of rigorous college prep courses will not improve his college application. It sounds like this option would be great for many who may want ancillary medical field options for their post HS career and exposure at this level will help them decide the tech school option upon HS graduation.
For medical fields that involve a college degree- including medicine, nursing, pharmacy, PT, OT- it would be best to prepare best with the most rigorous HS classes. Volunteering or other means of exposure would be the way to go to figure which fields most interest him.
I can see why this program is interesting to your son but it also seems as though the program is aimed at tech school, not college level, careers. Sounds excellent for those students. btw- physician here and I do appreciate all of the expertise those without bachelors and beyond training bring to patient care.
There, as mentioned, is plenty of time for him in college to consider if medicine is the path for him instead of many other related fields.