Disabled iPad won't update and restarts when software update reaches 99%

My dad gave me his client's iPad for me to fix. It was disabled, so it's going to be a short fix (Client provided me the login info for the iCloud).

However, when I tried restoring the iPad (through iTunes) and updating the iOS software update until 99%, the iPad restarts itself and iTunes pops out an error, saying that iTunes can't connect the iPad and needs a passcode (I'm connected to the proper USB Ports and the cable is okay). Tried safe third party software, but needs payment.

I really want to get this annoying error fixed.