Earlier quoted context omitted.
Rust + WebAssembly may be a little more difficult but they're both languages that are growing very fast and being able to take advantage of that now before they get bigger then they already are is a great idea long-term. It may take a while but is it better to learn something fast or well?
Neither one is foundational to web development. If you were to push most beginners to Rust, they'd likely quit before ever tasting success. The "fast or well" equivalency is a false one. Rather, a beginner should focus on learning the basics first. You don't put a first time driver in a Ferarri...Rust is a Ferarri.
I never said they have to learn all that all at once... I was simply giving him a list of languages and frameworks that would help him in the future.