However they are one ~30, with previous experiences of coding only at hobby level (C course, but he has the ability to translate ideas into C easily) and one ~40 years old (which used to be a PHP programmer, but is not doing serious/complex stuff for years at this point).
What is the simplest way for them to learn something that will bring a job ASAP? For example Android development? Node.js? Ideally this should combine a reasonable learning curve, the ability to work without knowing the whole computer science stuff, but just specializing into something, and should be a currently very requested technology.
Thank you a lot for any reply!
EDIT: I forgot to say that one has knowledges about Digital Signal Processing (in the field of music), and one is fluent with HTML/CSS (but not Javascript).
EDIT2: Thanks a lot for all the replies! This is very helpful.