What can honestly be said to people that ignore COVID-19 restrictions?

[thucythucy]

6. Ask them to imagine a scale.

On the one side place the inconvenience of upping their precautions until they are able to receive the proper vaccinations.

On the other side place the deep and lifelong grief, anguish, anxiety and probably also the anger their child will feel should either or both of them die.

I was a teenager when I lost my mother to cancer, I can attest to the fact that this loss has been a lifelong trauma.

In their case it seems to me their child will have to wonder--did they not love me enough to take the necessary precautions? Did they care so little for my emotional well-being that they weren't willing to accept these relatively trivial and time-limited inconveniences to insure they were there for me as I entered adulthood?

Taking these risks is basically telling their child they don't give a fuck about their role as parents. That's perhaps too blunt a way to say it, but it's how I read their behavior from what you describe in your post.

And that's not even considering the risk they are taking of infecting the child directly.

That would be the approach I'd try.

I'm hoping this might be helpful. Best wishes as you continue to deal with this painful situation.