The truth is what many of us consider to be basics - big O notation, b-trees, so on are not really needed by the average programmer. They might be useful (I get use from them) but they're not necessary.

Likewise, getting into intimate discussions on file encoding or strings in memory just isn't going to be retained by someone whose major interaction with a computer is facebook.

Focus on practical tasks, but take time to explain what code is doing in plain english. If you've done rubber duck debugging, you're aiming for that level of simplicity in your explanation. Avoid technical words, use simple metaphors and generally avoid the history lessons. Once you establish a baseline of skill in the developing programmer, swap the roles - have them explain their code to you.