I”m sorry to tell you there’s nothing anyone here can do for you. If you have an apple store nearby it’s been said that you can take the device and the original proof of purchase (in your case you may also need the death certificate) and they may be able to wipe it for you. I have no experience with this to know for sure.
If they do wipe it it will remove everything on it and the device would need to be set up as if it were new