Need to backup a different phone to iTunes
My dad has an iPhone 5s, and he is interested in upgrading to iPhone 6. he has not backed up his phone to a computer at all, so from my past experience, he will not be able to sync all of the apps on his phone to the iPhone 6 over iCloud.
I am trying to create a backup of his phone on my Macbook Pro, so that when he gets the new phone, I can just restore it from the backup, and he will not lose all of his apps, and logins.
When I connect his phone to my macbook, it only gives me the option to set up a new phone, or restore from one of my backups. it does not give me options to manage his phone to back it up.
How can i do this when my iTunes is already synced to my phone? I tried to create a new library and connect his phone, but it gives me the same options to set up a new phone, or restore from one of my backups.