The battery will be dead by the time you return if you leave it in the vehicle, also considering the type/quality of OEM battery used by Honda you might also not be able to recover any usefulness out of it if it's a few years old and you let it completely drain.
If you have some indoor hardware space I suggest disconnecting the battery and connecting it to a trickle charger indoors. I'm presently on an overseas trip myself so I have my wife "warm up" my 1999 Accord and my 2008 Pilot for 30 minutes once a week, but that will not be sufficient for the Passport so we usually put her own 2020 Passport Touring on a trickle charger when it's not being driven.
