I'm sorry to hear that you're having issues!
Could you please describe the issues you're experiencing with WebUI?
As for ping reboot, it is indeed possible to configure it via SSH. The solution offered by aclemence is also valid.
The easiest way to configure these rules would be using UCI. All of the options that can be configured can be seen by entering this command:
uci show ping_reboot
The default values look like this:
Then to edit these rules, UCI set can be used:
uci set [email protected]_reboot.enable='1' (this will enable the ping reboot)
When all of the desired fields are configured, uci commit command can be used, which will push all of the updated values to config files.
Let me know if there are any further questions!