iTunes and iBooks are obsolete, having been replaced with Music (which is more narrowly focused on — music) and Books. In macOS, Finder has taken over the backup role for iPads and iPhones that used to be in iTunes. (Simply connect the iPad to the computer with a USB cable then open Finder and Violá your iPad appears click on it and you are asked if it is okay to connect. After that backups are automatic every time you connect). iCloud backups are even easier, simply turn it on in settings then leave your iPad charging overnight. Unfortunately my instructions were based on more recent versions of iOS/iPadOS and macOS and I don't have resources to dial back to whatever version you have to use as an example and incompatibility rears its ugly head when iOS/iPadOS and macOS versions get too far apart in time.
The remove and reinstall I suggest might work, but isn't available in your version of iOS. I would suggest taking the iPad to the Genius Bar at an Apple Store but the iPad 2 is officially obsolete and no longer supported so they would not help you (at least officially). Even removing iBooks and re-installing it runs a substantial risk that a compatible version of iBook or Books may not be available on the iOS App Store for reinstallation.
In other words: I have nothing to offer in the way of a solution.
