If your camera was broken, a new rear camera may fix it. If your camera is not broken it's likely a problem with the power button flex. Another possibility is a logic board or software issue, but I've rarely seen that.

Error 53 has been removed as an obstacle to restore. Touch ID will not work but the device will restore properly now. https://techcrunch.com/2016/02/18/apple-apologizes-and-updates-ios-to-restore-iphones-disabled-by-error-53/