According to p.97 of the user manual:
"The date and time settings will be returned to the factory default settings if the camera is left without the battery for approximately 1 day. The settings will be canceled more quickly if the battery was only loaded in the camera for a short time before being removed. Before taking important pictures, check that the date and time settings are correct."
With most cameras that state this, it usually means that there is a capacitor mounted on the motherboard that is used to maintain the date and time settings when the battery has been removed. It is kept charged by the battery.
Other cameras can say that the date and time will be maintained for 10 days, 14 days or even 1 month in some cases but they usually have a rechargeable coin cell battery mounted on the motherboard and this is why they can maintain the date and time settings longer when the main battery is removed from the camera.
If the date and time defaults very soon after the battery has been removed the capacitor most probably is faulty or there's a problem with its charging circuit or even the battery if it doesn't last that long either from the fully charged state.
With regards to the memory card it could be a faulty card reader not latching the card properly or even bent pins in the card reader. Worst case would be a faulty motherboard
Unfortunately I cannot find a service manual or even a teardown video online for the camera which may help to open the camera so that it can be checked.