Yes, all countries historically related to UK (UK itself, USA, Canada, Australia, New Zealand) are very, very red.

It's not uncommon in my country neither (Serbia) that children accept their old parents to live with them. You're actually considered somewhat rude here if you send your old parent to go to a retirement home, unless there's a very good reason for it (like, you're constantly on business trips so you can't be much with your parent anyway, or you parent has serious dementia or other problem that makes him/her dangerous for your own kids).

I'm looking forward to hear about how it played out for your brother and sister in law in about 15 years. 😀 😀