Also, 'planting seeds' might not be the best term to use on this... LOL.
So, in reality, I think this seems like a slightly manipulative effort toward something that has no return (kind of). I mean, if he is a good Witness, no seeds would be planted. If he's not, then there are better (and easier) ways to go about this.
In attempting to concentrate on application, you might be missing the bigger picture that could possibly lead to a more productive oppritunities for his advancement away from the organization. For example in the Twilight Zone episode with the hypochondriac, there are A LOT of different themes going on. Yes, you can make the link between selling your soul to the devil and selling your soul to the WT, but there are themes of arrogance, preoccupation with one's self, presumptuousness, and the reality one must face when they live in a fantasy world. ALL of these apply to JWs.
However, if I were in your shoes (personal opinion), I would probably mention the differences between this and the Faust story on which this episode was based. Whereas the hypochondriac was high-strung and stressed upon making a deal with the devil, Faust did so out of boredom. But in both cases the journey of human emotion is displayed with this constant struggle to maintain “thrill” or importance. Making a deal with the devil is not the worst part of the story. The worst part of the story is the numbing power of arrogance and the box it puts us in... and have a discussion with him on that.
In this way, your are displaying something he is not allowed to experience: A greater understanding of human connection through literature NOT produced by the WBTS. I don't know if I'm getting this across successfully or if it even makes sense, but I guess the point is that if you really want to get him to think, don't point out the obvious in TV shows or movies... get to the gut of it and show him a few layers he perhaps wouldn't normally see. It is in those layers that are discouraged by the WBTS that will get him to think with more traction.
Hopefully. I think. I don't know, it's just a suggestion.