THAT is why you need all the advance notice! We have a cat that knows when it has a vet appointment. She disappears to who knows where. Missed the last one, figured out she isn't due for the mandatory rabies shot until next year so we got a reprieve.
Do they own the place in the mountains so they have somewhere to live after this weekend?
Works if the house is 3' off the ground and the ground is > 20' above sea level

Have to admit though, doesn't sound like dear brother thinks things through real well.
I'm sure it is a very nice house. If he is really lucky he can still say that in 2 days time.
Except that "mandatory" doesn't mean "get out or we will drag you out". It means "if you choose to stay we aren't going to come rescue you when the SHTF and the power is out and you are crying 'come save me!!!!'"