Upvote:3
Third country nationals can only benefit from EU law when they join or accompany an EU citizen making use of their treaty rights in the UK. That's true for short-term visits (with or without EEA family permit) and for longer term stay. If they live with their EEA citizen sponsor, they are certainly allowed to study in the UK.
Otherwise, they are still allowed to work or study but under the common immigration rules (which might require some expensive visa or to meet rather onerous requirements depending on your exact situation).