If a family does not have all the family members linked up within Appointuit you can fix this via the patient search facility in the Appointuit dashboard.
To start you will need to login and proceed to the search page [Settings > Patients] from there you can search for the patient via a few options, such as medicare number, name or email. Once you find the patient, click on the settings icon () and you should see something similar to the image below.
On the left you see the auto added family members (Sarah and Oscar) which show up their because their medicare number matches exactly with Johns, however if there is someone missing for various reasons such as different medicare number you can look them up in the search box on the right.
From there you can click the "+ add to family" button and that's it! That person will now show up as a option to make appointments for in the app and the 'child' account should now look like this
and the 'parent' or main account should now look like this