If your phone is under Android 4.1 or higher, you can install the latest version of WhatsApp. Installing an older version may cause malfunctions of the app.
Hello! I'm sorry to hear that you're having trouble getting WhatsApp to work on your old Galaxy Note. It sounds like the issue may be related to the date and time settings on your device.
One thing you can try is to manually set the date and time on your phone. To do this, go to the Settings app and look for the Date and Time settings. Turn off the option to set the date and time automatically, and then set the date and time manually to a date that is close to the time when the old version of WhatsApp was released (2017). You can try setting the date to January 1st, 2017, for example.
If that doesn't work, you may need to look for a more recent version of WhatsApp that is compatible with your device. You can try searching for an older version of WhatsApp that is more recent than the 2017 version you currently have, but still compatible with your device.
Finally, if all else fails, you may need to consider getting a new phone for your gardener, or helping him to find an affordable option. There are many inexpensive smartphones available that should be able to run the latest version of WhatsApp without any issues.