To fix a not working keypad, you may first try to restore or flash update to any latest device flash firmware available. And you may then do a hardware check up and replacement if the firmware flash update doesn't fix the problem.
First check the keypad flex matrix assembly for possible damaged, and then replace it if found so. The layout below shows the connection of each certain keys and its divided into groups of columns and rows for easy tracing if there is only one or two keys that doesn't work.
Nokia E63 Keypad Filter IC Jumper Ways Solution
If the above procedures doesn't help, there is a possibility that the problem lies on a faulty CPU IC.
Only reworking or replacing it might only fix your Nokia E63 keypad function failure problem.