A father died without bequeathing a third of his estate to a specific purpose, should we give it out of the inheritance or not?
If the reality is exactly as what is mentioned in the question, it is not Wajib (obligatory) for you to give out one third of the estate. However, it will be good if those of legal age amongst the inheritors give Sadaqah (voluntary charity) on your father's behalf out of the estate or any other money. (Part No. 16; Page No. 286) May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions.