If polish is going to be his 13th language and he has already strong bases in russian and eu languages, I don't see why it should be impossible. Keep in mind that is not true that is one hour. Is all his life learning other languages that is applied here. (there's a famous quote among artists about this that i cannot remember right now...)

Anyway my point is, that you are able to pick up CoffeeScript in one hour if you are fluent in javascript and python, aren't you?