Challenging a Sibling's Power of Attorney Over an Incapacitated Parent

Attorney Answer

Start with the document, not the family history — get a copy of the power of attorney and see what it actually authorizes, because the fastest way to undo an agent's transfers is usually the wording of the instrument, not proof of undue influence.

Idaho Code Title 15, Chapter 12 is the Uniform Power of Attorney Act, and Idaho Code § 15-12-201(1) is the provision that matters most to you. Certain powers — including the power to make gifts — must be expressly granted in the power of attorney itself. An agent who transfers the principal's assets gratuitously without that express grant is acting outside the instrument, and those transfers can be invalidated. That is a documentary question you can begin answering as soon as you have the instrument and the account records in front of you.

The Idaho Supreme Court took exactly that route in Smith v. Smith (In re Estate of Smith), 164 Idaho 457, 432 P.3d 6 (2018). Applying § 15-12-201(1), the Court upheld the invalidation of an agent's asset transfers because the power of attorney did not expressly authorize gift-making. The case also addressed undue influence separately: a rebuttable presumption of undue influence arises where a beneficiary of an instrument was also a fiduciary of the person who executed it and the record shows a nexus between the fiduciary role and the instrument's creation, and the fiduciary then bears the burden of rebutting it. Two things to understand about how that case fits yours. First, the transfers were unwound on the statutory ground, not the undue influence ground — so read the document before building a case around influence. Second, Smith arose in a probate contest after the principal had died, while your mother is living; the § 15-12-201 reasoning carries over, but the procedure does not.

What you describe as your real goal — freezing your brother's access to your mother's accounts — has a specific tool, and it is not a challenge to the power of attorney. Idaho Code Title 15, Chapter 5 governs guardianship and conservatorship, and Idaho Code § 15-5-401 is the provision under which an interested person, including an adult child, may petition for appointment of a conservator over the estate of a person who cannot effectively manage their property. A conservator appointed by the court supersedes and can check an agent's authority. If your concern is money moving now, that petition is the step, and it can be accompanied by a request for immediate protective relief.

One boundary you need to be clear about: the Idaho court has no say over the land, the oil royalties, the adoption, or the heirship questions arising from a North Dakota reservation. Those are governed by tribal and federal Indian probate law and belong in that forum, with a lawyer who practices there. And an honest word on the half-sister: a father's lack of a relationship with a child does not, by itself, end that child's rights — the absence of a relationship is not a termination of parental rights, and whichever probate forum has jurisdiction will decide heirship on its own law and records.

What you can do

1. Obtain a copy of the power of attorney. Ask your brother, the care facility, and the bank in writing. If everyone refuses, that refusal itself is something a court can address. 2. Read it against Idaho Code § 15-12-201(1) and look for one thing specifically: does it expressly authorize gifts or transfers to the agent himself? If it does not, any gratuitous transfers made under it are vulnerable. 3. Request your mother's account statements and the royalty payment records, and identify specific transfers by date and amount. Generalized concern will not support a petition; a list of transactions will. 4. File a petition for appointment of a conservator under Idaho Code § 15-5-401 in the magistrate court where your mother resides, and ask about emergency or temporary relief if funds are actively being moved. This is the mechanism that restricts access, and it is the one that matches what you say you need. 5. Gather medical documentation of your mother's condition and capacity, including when the stroke occurred and her condition at the time the power of attorney was signed. Capacity at signing is the other route to invalidating the instrument. 6. Retain separate counsel for the North Dakota tribal land, royalty, and probate questions. An Idaho lawyer cannot resolve those, and combining them into one matter will slow both down. 7. On fees: anyone who quotes you a figure without reading the documents is guessing. Ask each lawyer whether they charge hourly or a flat fee for a conservatorship petition, what the retainer is, and what happens if the case is contested. Contingency arrangements are uncommon in this kind of matter because there is no fund recovered up front. Contact Idaho Legal Aid Services and the Idaho State Bar's lawyer referral service before assuming you cannot afford representation. 8. Note for later: Idaho's current guardianship and conservatorship chapter is effective until January 1, 2027, after which Title 15, Chapter 5 becomes the Uniform Guardianship, Conservatorship, and Other Protective Arrangements Act and section numbers will change. Confirm the current numbering when you file.