It is rare you find something on youtube on religion which feels fresh, but this did it for me.
Most here properly agree that the best (only) way to have a constructive conversation with JW who is in is using methods such as those described by Steven Hassan. However if you search youtube or the internet, most discussions on faith takes the form of debates or at any rate discussion about factual things -- exactly the things Steven Hassan would tell you is the least likely to work.
I came across a series of youtube videos with a guy who is basically walking around with a camera and interviewing people on their beliefs. One can ask if that isn't a bit to preachy, however the interesting part is he follows a carefully structured dialogue which (too my mind) is very much inspired by work on cults and deprogramming. Specifically he focuses on using the socratic method (only ask questions) and the purpose of the dialogue is to make it clear to people how strongly they believe the things they believe, why they believe them and in turn make them question if those reasons are really that strong.
Obviously he is doing it from an atheistic perspective, however I think it is very beneficial to see for christians too since an atheist or christian face the same problem with family or friends who are in, namely how to make people question a belief structure which is firmly in place without triggering the cult personality.
His youtube channel is here:
To get an idea about how this works, suppose you were talking with a jw. The sort of questions you would ask is first how strongly the person believes in God (you could alternatively ask, that jehovahs witness is gods organization), and to indicate that on a scale from 0-100 with 100 being absolute certainty and 0 being maximal doubt (this is very thought trough. He explains elsewhere he is using this scale rather than say letting 0 be there is absolutely no god to introduce the idea of doubt early on).
He will then ask for why the person believes this is the case; if different types of justification is given he will ask the person to divide them into a pie-chart say 40% evidence and 60% faith. He will then try to approach whatever reasons the person gives using follow-up question and never assert something as being factually wrong, typically using a version of the outsiders test of faith. Say for instance the person says he or she believes God exists because of fortunate things happening in his or her life, he will ask if she would believe less in God if unfortunate things happened, or if fortunate things could happen even if you did not believe in god, or give an example of a Muslim who said Allah existed because of fortunate things happening in her life.
Suppose the topic is evolution. An a dub says:
I don't believe in evolution because it has never been observed.
So instead of saying: Evolution is not a belief, evolution has been observed, macroevolution can't be observed bla bla you rather ask:
Just to clarify, what do you understand evolution to be in this context?
Can you give an example of what in your view would be an observation of evolution?
with follow up questions like:
Can things only be known to be true if they are observed?
The approach he is following is directly influenced by Peter Boghossians "A manual for creating atheists", however I am much more impressed by the approach taken in the videos than with the book because it's a lot easier to see how it is supposed to be implemented and he isn't as preachy as Peter (like, he advocates you should chat people up on their beliefs if they are sitting next to you on a plane, yikes).