Spell out everything that your hypothetical friend would have to go and learn for you to feel comfortable giving him even the most junior-level coding responsibilities or vouching for him as a "yeah, this guy can do the job" to a professional contact of yours. Write it all down, show it to your dad, and spell out the effort involved. That's what he's looking at learning in order to be taken seriously in the marketplace.
(I'd venture that some kind of consulting/contracting is what he'd wind up doing, both because I don't think many companies would take a resume like his seriously for a junior developer position and also because I don't think someone who's been at the top of the org chart would tolerate going to the bottom of the org chart for very long.)