Cannot Login to iCloud on iPad mini

Hi there

I have an iPad Mini running 8.2

My dad is undergoing chemo and his brain is a bit frazzled. Somehow he changed his password before Verifying it and it is stopped in a loop. A pop up window asks for the password and when entering it, it counces out. On the settings page, it shows the same id as I am signing into and when I upgraded on my mac www.icloud.com to a 5GB storage, it updated the total from 1GB to 5GB on the ipad, yet I cannot access anything to do with the iCloud seetings on the ipad. Another pop up says "Verification Failed". he turned on "Find my iPad" and it won't allow us to reinstall. His icloud account works on my Mac, my phone and iPad, but not on his! It is so frustrating. Also iMessage and Facetime will not accept the new password for his Apple ID.

So we have an iPad Mini which is logged into his account. A working iTunes and iStore username that will not work with iCloud, Imessage and Facetime. All have identical user names.

Please somebody help me!

Thanks

Rob