Jessica Cameron went to see her accountant and established a discretionary trust and transferred her assets into it. On 1 July 2021, Jessica signed a deed of trust appointing her brother Hamish to be the trustee of the Cameron Family Trust. On 1 August 2021, Jessica was awarded the sum of $1,200,000 by way of judgement of the Supreme Court of the Northern Territory in relation to a medical negligence action against her plastic surgeon, Dr Strange. On the same day, Jessica signed a letter addressed to Hamish which said "I transfer my right to be paid the sum of $1,200,000 which was awarded to me in my medical negligence action into the Cameron Family Trust." Sometime in 2000, Jessica had a secret love affair with a member of the boy band "N-Sync" and in 2001, Jessica gave birth to a son, Joshua, who was a child of Jessica and her secret lover. Jessica kept the existence of her child a secret from her family for fear that she would be disinherited from her family's gas and coal mining empire. Joshua was sent to live with a close friend, Fiona Clarke in Sydney to care for. In October 2021, on Joshua's 20th birthday, Jessica told Fiona that she wished to benefit Joshua in her will but she did not want her family to know. She asked Fiona to help her. Fiona agreed. Jessica told Fiona that she had placed a number of documents in the safe custody of her solicitor and had instructed her solicitor to only release those documents to herself and Fiona. Jessica said that the documents would explain how to help Joshua if she ever died. In 8 January 2022, Jessica prepared a new, valid will at her solicitor's office. Joshua, her son, was employed as a law clerk with the firm where Jessica prepared her will and he and the solicitor who drafted the will witnessed it. The will contained the following provisions: 1. I appoint my dear friend Fiona Clarke as my executor. 2. I give the sum of $2,000,000 to my dear friend, Fiona Clarke. 3. I give the rest and residue of my estate to my only surviving brother, Hamish. On 14 February 2022, Jessica passed away in a motor accident. Fiona retrieved the documents held in safe custody with Jessica's solicitor and apart from the will, a letter addressed to Fiona, signed by Jessica, dated 8 January 2022 was also found which said: "Fiona, I have left you $2,000,000 in my will. Please give $1,900,000 to my son, Joshua and keep the rest for yourself."

What are Fiona's obligations regarding the $2,000,000 gift in Jessica's will? Does the fact that Joshua witnessed the will have any impact in light of section 12 of the Wills Act 2000 (NT)?