All purchases are tied to an AppleID, and the AppleID is tied to a country. You can only download purchases from the App Store for the country of your AppleID. When you purchase software or want to update it, the device should be set to the country of your AppleID. As your purchases are only valid at the AppStore of your country, you can only family share with family members with an AppleID of the same country.
When you are travelling, the installed software on your devices will continue to work, even if you are in a different country. Just do not change the region settings on your device. Continue to use the same AppleID of your home country abroad.