Nothing gets through to anyone invested in an idea, be it religious, political, or otherwise. People change when the pain of changing is less than the pain of not changing. Allow them the [in]dignity of figuring it out for themselves.

I'll answer a theist's questions but I don't expect them to deconvert on the spot. It's normally a gradual, private process.

If you need hope, just remember every deconvert you meet has gone through that process. They just didn't give anyone the gratification of being solely responsible for their enlightenment.

It is the perfect scam. I mean, come on, if you don't pass it on to your children and everyone you know, you will literally burn in a big old fire and be tortured for eternity.

Nothing for it, smile and nod and go about your business. Atheism doesn't require you to proselytize.

I consider it a form of child abuse.

I managed to stop Jehovah's witnesses coming to my door because I was converting too many of them!

Yes, I don’t really care what nonsense adults believe, but brainwashing their children is a different matter. Children are not born religious, as Dawkins says” there is no such thing as a Muslim or a Christian child, there are only children”.

Nothing you can do for them.
But you can train them NOT to being up religion by simply ignoring them whenever they do, murmuring "Um, hum, that's nice," while looking bored, then leaving the room every time they bring it up.

Only look at religious people and smile at them when they speak on neutral subjects in a friendly manner. This quickly trains them to avoid religious subjects.