Find My iPhone

I'm seriously frustrated with Find My Iphone. How am I supposed to find a phone for my husband if it sends two-step verification to the missing phone? Normally when you lose a phone, you are OUT somewhere, not in your house by your other devices. Find My Phone used to work miraculously. You should be able to log out of Find My Phone, log in as new Apple ID, and find the device -- presto! Please provide instructions on how to do this without iCloud etc.