He seems to be a total novice to the use of chords, so surely he needs to know the basics of chord progressions at the very least.
Which is why getting into chord substitution is a terrible idea. Someone who has never written a simple 3 chord song wants to stuff 13b5's and God knows what else into his noodlings because "the more, the better".
PS – I was just fooling around with "This Land Is Your Land", telling BIAB to "jazz it up". I had to stop because I was afraid if I kept going it might start to sound good.