Mauricio Umansky is taking legal action to protect his father.

The Real Housewives of Beverly Hills star and his sister Sharon Umansky Benton have filed a petition for conservatorship over their 81-year-old father Eduardo Umansky, E! News confirmed.

According to the legals docs filed Aug. 15, the siblings claim Eduardo's girlfriend was using his inability to "resist undue influence and fraud" to benefit off him financially and that he is unable to take care of himself and his assets.

“Over the course of the past few months, PC's [proposed conservatee] girlfriend has become more controlling, limiting and regulating who the PC can visit with,” the filing claimed. “She has begun to isolate him and is trying to get married even though they have been together for twenty years and never decided that they wanted to marry.”

Mauricio and Sharon specifically cited one instance where they took Eduardo to lunch without the girlfriend's knowledge. When she learned of the outing, they claim she became "enraged, verbally and emotionally abusing the PC."

In addition to the alleged abuse, the two claim his girlfriend—who they did not name—has taken nearly $300,000 of his money.

“Over the course of the past eighteen months, PC [Eduardo] and the Petitioner [Mauricio] have discovered that [the girlfriend] has taken, secreted and appropriated more than $260,000 from PC through undue influence, whether physical or emotional, and/or fraud," the petition states. “During this time, he has written more than $260,000 worth of checks to his girlfriend for no reason other than she wanted it."

Attached was Eduardo’s signature consenting to the conservatorship and nominating Mauricio and Sharon as co-conservators.

If granted the conservatorship, they would have legal control over Eduardo’s person and estate. A hearing has been set for Oct. 28.

Keep reading to look back at Mauricio's family album.

Kyle Richards and Mauricio Umansky enjoy an Italian family vacation in August 2023 with daughters Farrah, Alexia, Sophia and Portia.

The group glams up for a fabulous boat ride in Italy.

The group attends the June 2023 Aspen wedding of Kyle's niece Whitney White.

Ever the festive family, Kyle and her four daughters match on Christmas in red PJs.

"Happy Father's Day @mumansky18," Kyle wrote in June 2023, "so grateful that our girls have such an incredible Dad."

The reality star added, " Leading them with love and instilling in them to be adventurous and live life to the fullest. Always there for them and not knowing how to say "no" They would definitely agree you get the best Dad award."

Kyle shared a throback pic of Portia and Mauricio flashes adorable smiles.

"Luckiest Mom on earth #nationaldaughtersday," Kyle wrote in September 2023. "Love my girls."

The brood poses with other notable members of their extended family, including the Hiltons and Kim Richards' daughters.

The brood lives it up in Las Vegas.

"Merry Christmas to you and yours," the reality star shared in December 2022.

Mauricio enjoys a spa treatment from his youngest.

The fam tours some Washington, D.C. monuments.

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