C++ is famously hard. I know C++ for at least 15 years, made a reasonably successful side project in is, worked professionally for 2 years, and I still don't think I should teach it to others. I could probably do a decent job, but if they ask me about SFINAE or modern (after C++11 with bits of 14 maybe) features or "is this snippet UB" I would have to concede. Learning C++ in a week good enough to teach it is a cruel joke and laughing students straight in their face.