Limits on Technology (teenagers)

R.

I have a 19 yo, 16 yo and 14 yo and they are ALL addicted to technology. The oldest has been on his job 3 years and is in college. The middle one (my daughter) is an AB student who reads, crochets and plays the saxophone. The youngest only wants to get on a laptop, tablet, desktop computer, smart phone or smart TV and either watch YouTube meme, vines, gameplaying or other nonsense videos or play video games himself-- no drive or motivation towards anything unless it's "fun" or requires no work!

Unfortunately these habits started with their father (his addiction to video games is part of the reason why we are divorced) and they lived with him full-time while I attended college and lived in another state.

The youngest 2 have come to visit me, and are about to return to their father. Is there something I can expose them to that can work on breaking this addiction?

Now, with much prodding, he says he either wants his own YouTube channel, be a coder or perhaps do CAD design so he can be a 3D printer. All of them require work, which I explained to him. We started working on the YouTube channel but when he seen how much work is involved, he's gone uninterested.

Links to books, videos, lectures, programs, etc., etc... I'm DESPERATE for help for them. Can these addictions be broken or cured???