I think the most likely option is moving geolocs for water-access safety and heat concerns.
I've recommended an emergency battery system for their house / air conditioner, a reserve stock of water in the house, a "go bag," and an escape plan to the mountains. Longer term, they are realizing that their primary residence risks unhabitability in summer months. I realize they're in a privileged position, though.
What prep did you recommend to your parents? I’m interested for what I can reuse or adapt.