super late followup - but I did ask support via a ticket and got the procedure for adding the sky voltage to the normal app gui. Worked fine.
"add the battery card through the app! Open the app and go to Settings > Stations > choose the station > Advanced > Enabled Battery Card. This should toggle the SKY device’s battery on the Observations Page. "
(thanks Chelsea)
Also got the family member to let me log into their account so I could add an API key for me to monitor things in more detail remotely…