A petition was filed in 6th District Court in Livingston Thursday by Steinman asking for the court's permission to become Prophet's legal guardian.
The decision is a result of Prophet's undefined neurological disorder, which was announced earlier this year, CUT spokesman Christopher Kelley said Friday.
Prophet, 59, has said the illness hinders her memory and ability to process new information.
Despite needing help with her day-to-day affairs, Prophet is still able to take dictations from the Ascended Masters -- a key part of her role as spiritual leader, Kelley said.
"It's a personal decision she reached after much thought and consultation with her attorney," he said.
Kelley said while CUT members respect Prophet, their real attraction to the church is its teachings.
The court papers state that Prophet should be made a "protected and incapacitated person" because of her illness.
The papers list her total assets, which Steinman will control, at about $95,000. In addition to these assets, Prophet receives a monthly salary of $8,000 from the CUT.
Under the petition request, Steinman has the ability to approve or deny medical treatment of any kind to Prophet.
No date has been set for a hearing on the request, said June Little, Park County Clerk of Court Friday.
The guardianship announcement came in a letter -- which was attributed to Prophet -- released to church members Thursday.
Prophet's elder children are not happy with the decision to turn over control of their mother's financial, medical and legal decisions to Steinman, according to a prepared statement issued Friday by Erin, Sean and Moira Prophet.
The validity of Prophet's letter is doubted by her daughter, Erin Prophet.
Erin Prophet, 32, a writer who lives in Livingston, said the quotes in the letter do not sound like things her mother would say.
Kelley maintained Friday the letter is authentic.
"It's the real McCoy," he said. "Murray is doing this at her request."
Prophet is expected to discuss the situation during a spiritual conference this weekend in Ottawa, Kelley said.
"She's fully aware of what's going on," he said.
The decision came as a surprise to her son Sean, 34, who works in Los Angeles as a video editor.
"The first I heard of it, I got called out of an edit session and there was Murray on the phone with two attorneys," he said in the statement issued by the children. "It was obvious that he had all his ducks in a row before he called me."
Steinman defended his actions and said he "empathized" with the children.
"I've known the kids since they were very little," he said. "I reach out to them with my heart
"I don't know if anybody's implied that there is anything sinister going on but there isn't," he said
Steinman first rose to prominence in the CUT during the church 5 bomb shelter phase in the late 1980s.
Steinman said in a press release that Prophet has given a lot to him in the past and he is glad to have a "small opportunity" to give something back. "I couldn't find it in my heart to say no, he said.
Legal action explained By Enterprise Staff
A guardian and conservator would take care of another person, as well as their assets, said Livingston attorney Kent Douglass.
Murray L. Steinman is trying to become the legal guardian and "conservator" of Elizabeth Clare Prophet, the spiritual leader ot the Church Universal and Triumphant.
Douglass said a guardian is a person appointed by the court to take charge of the day-to-day affairs of another person.
A conservator would be appointed by the court to take care of another person's assets, Douglass said.