Elder person forgot AppleID PW and Ipad passcode

My dad suffers from memory issues. He has forgotten his password for his apple ID as well as the passcode for the iPad. He can access the iPad and use it as his fingerprint is working. I can't recover his account without his passcode. i have created a new email & apple ID for him but I need to be able to reset his passcode, hopefully without resetting the device and losing his stuff.

Any suggestions