Most family / discretionary trusts will continue to have life after the death of the founders of the trust (usually Dad and Mum).
The key is who controls the trust after the death of the death of the founders? Consideration must be given to the terms of the Trust Deed and especially who the trustee and appointor / principal is. A short Deed of Variation of the Trust is often required.
With significant wealth in family / discretionary trusts it makes sense to obtain advice from an experienced estate and succession planning solicitor when making your Will about the effective passing of the trust assets to your desired beneficiaries in your desired shares.
Our Brisbane Will making and Estate Planning lawyers can help wherever you are in Australia. Ask about our initial 20 minute consultation (by phone or Skype) for a low fixed fee.