Dukes County manager Martina Thornton is involved in a tangled probate case in which she stands to inherit much of the estate of a longtime Edgartown resident who died 11 months ago.

Louis S. Stix died in December 2015 of cardio-pulmonary arrest at the age of 84. His will, signed 101 days before his death, is being contested by his daughter Margaret Stix, who claims in a sworn affidavit filed in court that Ms. Thornton prepared the new will, using undue influence to make herself and her husband key beneficiaries of the estate shortly after Mr. Stix was diagnosed with several forms of cancer. Ms. Thornton’s Boston attorney said Thursday that Mr. Stix and Ms. Thornton were longtime friends and there was nothing unusual about the case.

In the lengthy, detailed affidavit, Ms. Stix says her father, a resident of the Island since 1961, left an estate worth about $1.2 million. She claims among other things that he was living in a deteriorated home with no heat or plumbing near Ms. Thornton’s residence and had suffered from emotional and mental instability throughout his life. In the affidavit Ms. Stix also said she believes Ms. Thornton “held herself out as an attorney” to her father, though she has no license to practice law. Records in the case were obtained by the Gazette from the Dukes County Probate Court.

Ms. Thornton was appointed county manager by the Dukes County Commission in 2012. She was an unsuccessful candidate for county Register of Deeds in the state election last week.

Massachusetts law does not require that wills be prepared by attorneys, but the law does state that only a licensed member of the bar “hold himself out as authorized, entitled, competent, qualified or able to practice law.”

Reached by telephone Thursday morning, Ms. Thornton strongly refuted the claims made against her in court. “I have not represented myself as a lawyer,” she said in part. Ms. Thornton said she has a law degree from the Czech Republic but is not licensed to practice law in Massachusetts and has never claimed that she is. “Everyone I work with knows that,” she said, adding: “This is a private matter and it should be dealt with through proper channels in the courts. I am very unhappy that this is going to hit the paper. I don’t think it’s right that you are putting this out without knowing the other side. And I cannot tell the other side of the story without my lawyer.”

Speaking to the Gazette late Thursday her attorney, Brian D. Bixby, a partner at Burns & Levinson in Boston, said that Ms. Thornton had drafted the will, but he described it as common practice. “It’s not at all uncommon for a will to be drafted by a person who is not a Massachusetts lawyer or for that matter not a lawyer at all,” he said. “There is no requirement that a person drafting a will be an attorney. On the Cape and Islands a lot of people don’t want to go to the expense of hiring an attorney.”

The will signed by Louis Stix in late August 2015, four months before his death, leaves Margaret Stix and her brother Nicholas $10,000 each, and includes a provision that if either were to contest the validity of the will, they would automatically forfeit the bequest. According to Ms. Stix, the will replaced one executed by Mr. Stix in 1982, which bequeathed the bulk of his estate to his then-wife, Jennifer Stix, and his two children. The new will also names Patricia Gesner as a beneficiary of the estate, leaving her stock valued at about $190,000. Ms. Gesner is identified by Margaret Stix as her father’s partner. The will also leaves Ms. Gesner a life estate that allows her full use and benefit of the home Mr. Stix occupied on 9th street north in Edgartown for the remainder of her life. On her death, the will stipulates that Martina and Dana Thornton will inherit the entire property. Court records estimate the value of the Mr. Stix’s real estate at $630,000 and his personal estate at $600,000.

According to town assessors records, the Thorntons own a multilevel Cape on 9th street north and also vacant land on 8th street north.

In her affidavit, Margaret Stix said her father was in a fragile physical and emotional state following his cancer diagnosis on August 4, 2015, and that his health and living conditions had deteriorated substantially in recent years.

“During the final years of his life, my father lived alone in what can only be described as a firetrap, with no working plumbing in the bathroom and no working boiler,” Ms. Stix wrote in the affidavit. “My father also told me that he had occasional meals and sometimes showered at the home of his neighbors, who I later learned were Martina and Dana Thornton.”

According to court documents, on March 2 of this year, three months after Mr. Stix died, Ms. Thornton petitioned the probate court to name her as the special representative to the estate. (Formerly termed executor, a special representative is responsible for overseeing the probate process and distributing any assets as instructed in the will.) In his new will, Mr. Stix had designated his brother Daniel Stix and his ex-wife Jennifer Stix as personal representatives. Following his death, both filed waivers saying they did not want to assume the responsibilities of special representative. Also according to the will, if Mr. Stix’s brother or ex-wife are unable or unwilling to serve as special representative, the responsibility would fall to Ms. Thornton.

In her affidavit, Margaret Stix expressed suspicion over the naming of two special representatives in her father’s new will. “I believe that it is unlikely that my father would have knowingly nominated Daniel and Jennifer as his personal representatives because neither would have been willing or able to serve,” the daughter wrote in the sworn affidavit. “Daniel has been living in a nursing home in Connecticut since suffering from a major stroke, and Jennifer no longer spends much time on the Vineyard. I believe that my father was either unaware that he was nominating these individuals as his personal representatives or was so confused that he did not recall their current health and relationship with him.”

In April of this year, the probate court did not grant Ms. Thornton’s request to be appointed special representative for the estate, instead appointing Suzanne Fay Glynn as a special temporary representative. Ms. Glynn is a Falmouth attorney who had been nominated for the role by Margaret Stix. Her appointment has been extended twice by the court because the parties in the dispute cannot agree on who should permanently fill the role of special representative. Ms. Glynn’s appointment next expires in January.

Margaret Stix is represented by Joseph L. Bierwirth, a partner at Hemenway & Barnes in Boston. Contacted by the Gazette Thursday, he declined comment.

Probate court records contain no further information about the proceeding. But Ms. Thornton said the matter is in mediation and her attorney concurred. “We have a date set for the end of this month with a retired judge,” he said. “It’s a very common step in a will contest that the parties attempt to mediate and conciliate. The one common thread for all these cases is the key witness is not around to testify.”