Robert McCorkill's estranged sister and a group of supporters want the will thrown out because they say the National Alliance preaches hate and genocide.
"We do not accept those values in Canada, we simply don't," said Cathy Fawcett, who was in the Court of Queen's Bench in Saint John on Monday, representing B'nai B'rith. The Jewish group joined the case to argue McCorkill's will is dangerous.
"A gift to a group like the National Alliance would only exacerbate the problems we are experiencing every day," Fawcett told CBC News.
Anti-racism groups have previously said they fear the National Alliance could sell the items, and help spark a rebirth of the neo-Nazi group that has been in decline since its founder died more than a decade ago.
The collection in question includes Greek and Roman coins that are thousands of years old, an ancient Iranian sword, and more, according to a 55-page appraiser's report from August 2010.
McCorkill's sister, Isabelle McCorkill, stepped in last July to oppose the will, arguing her brother's last wish is "illegal."
It's not about the money, said her lawyer, Marc Antoine Chiasson.
"She felt the gift was offensive, and felt obliged to step in and stop it," he said.
On Monday, Chiasson referred to the National Alliance's handbook, reading passages aloud in court. The handbook, published in 2005, talks about the "holocaust mythology" and the need to maintain a "racially clean area."
It states members will do "whatever is necessary" to create a "white only" homeland in America.
Chiasson argued the handbook's writings "clearly promote genocide," constitute hate speech and violate the Charter of Rights.
Therefore, the gift itself is against the law and public policy, said Chiasson. He urged the court to quash the will, allowing his client and another living brother to benefit.
Lawyers for B'nai B'rith, the Centre for Israel and Jewish Affairs, and the government of New Brunswick made similar arguments.
Evaluating beneficiaries not role of court
The Canadian Association for Free Expression, however, contends the will should stand.
Paul Fromm, founder of the group, which has lobbied for Holocaust deniers such as Ernst Zundel in the past, does not believe a will should be quashed because it violates public policy. A man's last wish is paramount, even if the court doesn't like the beneficiary, he said.
"Would a bequest to a right to life group violate public policy? If this argument wins, yes it would," Fromm said.
"People should have the right to leave their money as they see fit."
Lawyer Andy Lodge, who represented the Canadian Association for Free Expression in court on Tuesday, argued "there is no legal basis to challenge Mr. McCorkill's will."
Lodge argued that quashing it would "get this court to go where no court has gone before," evaluating beneficiaries.
"If we open that Pandora’s box, there are many problems that could ensue," he said.
Lodge gave examples of groups and individuals been convicted of crimes in Canada, or whose beliefs may violate public policy.
"There will be outfall from this decision if the will is voided," said Lodge. "Are we saying the Hell's Angels can never receive a bequest? Are we saying no drug dealer can receive a bequest? What about Greenpeace?"
Lawyer John Hughes, who represented McCorkill's estate, also argued the will is sound and legal.
"No one has argued Robert McCorkill was incapable of making this request," said Hughes.
He also said the National Alliance is a lawful corporation in good standing that has never been convicted of a crime in Canada or the United States.
Initial estimates pegged McCorkill's collection, parts of which have been exhibited in Saskatoon and Ottawa, as being worth up to $1 million.
But probate court documents obtained by CBC News last summer showed McCorkill's estate willed to the National Alliance is valued at about $250,000, with about $89,000 in outstanding liabilities. That leaves about $161,000 for the white supremacist organization, which is based in West Virginia.
McCorkill was born in 1937, the son of a farmer in Ontario.
According to an affidavit filed by his sister, McCorkill attended the University of Winnipeg in the late 1950s, studying geology. He later became a professor, working at Carleton University in Ottawa. He spent time at the National Alliance's headquarters in West Virginia.
McCorkill died in Saint John in 2004.