Facing the Morally Bad Future

[Reforged]

I doubt that what you believe would shake your friends faith. Even if you had very convincing arguments that's not how faith works.they will continue to believe no matter what.

What will shake their faith is why I don't believe anymore.

You're partly right. I think some might keep doing what they're doing but there's definitely others that would look into what I've said and basically start digging their graves. These are the ones that I fear for.

Maybe, maybe not but every Atheist here has been down this road. The subject pops up with a Theist friend or relative, you calmly put across your view and the reasons why.
At first the conversation goes alright but then you come at a juncture where you've pinned them down, they have no room to manuver other than to get frustrated and end the conversation or admit they believe because they believe.
Continuing the conversation at this point rarely ends well and is often met with hostility because once you have reached this point they are no longer making any attempt to take a reasoned approach focusing instead on defending a belief they've followed all their lives at all costs.
The chances it will end better are slim at best.