You can easily check if your learner has a connected family member. In your community, just click the "learners" tab in your top nav menu. You will then be able to see all your learners within the community.
If the learner has an attached family member, you will see the family member's avatar on the learner card. Here's a quick video to show you where to find it.
Note: If you want to add a student to a family account, please check out this article.