Okay, let's ignore for a moment that, as cults go, JWs are "not that bad". The fact that, by their subtlety and innocuousness they can lull people into a false sense of security, as they are 'nice people' can be ignored for the moment as well.
Imagine that someone was investing in a pension plan, and that you KNOW this pension plan is going to leave them high and dry as it is a fraud.
You are in that situation.
You say;
"This young, confused kid may find fulfillment also. Does it really matter who she finds that with?"
Do I really have to answer that? Fulfillment? Yeah, the sort of fulfillment whereby if she gets suckered into it and wastes her life in it. I am sure that the Reverend Jones's followers had fulfillment, and the Heaven's Gate follwers, I'm sure they had it to.
Just 'cause the Witnesses don't usually kill you (although they'll stand by and let you bleed to death) doesn't mean they are not bad.
Now this doesn't mean you automatically should become a crusading knight and alienate your wife by being outspoken with your views; you're 50, you might feel it's easy just dealing with things they way they are, and that's okay. That's okay, that's your choice.
Now you're aware of the lie behind the truth I don't know if you'll really be able to sit there for the next twnty years smiling in the meetings; in fact, the very thought dwelled on will probably rot away inside you like a cancer it's so unappealing. But it's a new realistation to you; very few people here took the decision they took to leave the moment they began to realise, it's okay.
But I don't think it's your choice to decide that a young persons future be shrugged over as she'll be getting some form of 'fulfillment' in return for wasting her life in a cult.
I would look for a middle way; you want to avoid regretting standing by as the thought control techniques that mark JWs out as a cult wrap their way round this persons brain, as by the time you wish you'd done something, it might be too late for that person, and I guarantee you'll regeret not having tried sooner.
All the best in your journey.