Many parents believe that the level of work required by their child as a university student may be difficult for them to adjust to, but if your child has completed the ATAR successfully, rest assured that they have almost certainly prepared themselves to deal with a university-level workload.
The first year workload in particular should be manageable. If their time is managed effectively, your child should be able to complete all their work and still fulfil other commitments.
Most university students are busy people with busy lives. They manage their study around work, family, their growing social life and a range of other commitments. Encourage your child to follow up other interests in addition to their university workload, as there's no need to focus exclusively on study. They will still find plenty of time to follow interests other than study which can prevent them 'burning out'.
There is always help available to support students. The Learning Centre provides a range of free online programs and workshops to help students towards success with their study.