If this parent has set up Family Sharing and the child is part of his Family, he can also manage these Screen Time settings from his own device.) This parent was keen to get advice on what other alternatives he had (other that the option described by the article above), given that the app is 'allowed' by the 12+ 'age rating' he set up for Apps, in the Content & Privacy Restrictions of Screen Time (found in Settings) on the child's devices.