Joined the Mayqueeze.
I fear there won’t be a solution that doesn’t cost money somewhere. Please don’t buy 3 burner phone numbers at once. I would feel bad if it didn’t work and/or you get suspected of being a criminal.
Check your current phone subscription if you have one. There might be a way to get an additional number for free or very little extra. And it might be a good backup emergency service to have just with your parents maybe even if you go down a different route for the rest.
Anything other than Signal seems unadvisable from a privacy POV. Do you have a way of talking to them live on the phone, at the same time? You can try and register their Signal on a burner phone wherever you are. As they sign up, you sit on the call and give them the phone number and security code when it comes through. Unless having Signal on the phone is itself a reason to get arrested in Russia, which frankly wouldn’t surprise me either.
I don’t know if this will work. I did it on a different service using the number on a dumbphone to register for use on a tablet once.
To be fair to Google, they ignore everyone. All submissions are machine read and handled. The chance that a human is reading anything is exceedingly small. If you find an email address of an employee online, I’m sure it’s not their primary account and/or all non address book senders’ emails go directly to spam.
I’m sure the investigation of the infection here is good. The befuddlement over Google’s replies and non-replies is what I’m commenting on. In my experience, that’s unfortunately just Google doing Google things. They are no longer prohibited from being evil.