"A programmer may try to get you to install Python 3 and learn that. You should tell them, "When all of the python code on your computer is Python 3, then I'll try to learn it." That should keep them busy for about 10 years."
http://learnpythonthehardway.org/book/ex0.html (under Warnings for Beginners)
Someone wanting to learn Python (or any other language) will be better served if they are helped to focus at most important and least painful things first: in this case, python 2 is everywhere with huge number of libraries. Whatever you need is 'pip install' away.
Learning Python 2 is not a waste of time: whatever you learn and is changed in Python 3, will be easily relearned once it becomes needed.