Short answer

Yes. Under Idaho law, transfers made by an agent under a power of attorney (POA) can be challenged if the principal (here, your grandfather) lacked the required mental capacity when the POA was executed or when the agent made the transfers. Possible legal claims include lack of capacity, undue influence, fraud, forgery, breach of fiduciary duty, and conversion. Remedies can include setting aside transfers, requiring an accounting, returning funds or property, removal of the agent, and civil damages. You will generally need documentary evidence and, in many cases, medical or expert testimony to prove incapacity.

Detailed answer — what matters under Idaho law

Idaho recognizes that a Power of Attorney is effective only to the extent the principal had the mental capacity to execute it and understood the nature and effect of giving authority to another. If someone signs a POA while unable to understand the nature and consequences of the document, the POA may be void or voidable. Even if a POA is valid, an agent must act within the scope of authority and in the principal’s best interest. Transfers made outside the authority, made because of fraud or undue influence, or made while the principal lacked capacity, may be challenged in court.

Legal theories you can use to challenge transfers

• Lack of capacity: The challenger must show the principal lacked the mental ability to understand the transaction (the nature of the POA and its effects) at the time the POA was signed or at the time transfers occurred.
• Undue influence or coercion: If the agent or a third party pressured or manipulated the principal into signing the POA or into allowing transfers, a court may set aside the transactions.
• Fraud or forgery: If the POA or signatures were forged, or if false statements induced the principal to execute the POA or agree to transfers, the transfers can be rescinded.
• Breach of fiduciary duty and conversion: Agents owe duties to the principal. Misusing principal’s funds for personal benefit can lead to liability and recovery.
• Failure to follow formalities: If the POA did not meet Idaho execution requirements (witnesses, notarization if required for certain acts), the POA or particular acts might be invalid.

Relevant Idaho sources and where to look

Idaho statutes and court filings govern powers of attorney, guardianships, and remedies for elder financial exploitation. For the statutory framework and related probate/guardianship rules, start with Idaho’s statutes on probate, trusts, and powers of attorney at the Idaho Legislature website: Idaho Code, Title 15 (Probate and Trusts). For protective services and reporting suspected abuse or exploitation, see Idaho Department of Health & Welfare, Office of Adult Protection: Office of Adult Protection.

Evidence you will need

Courts generally rely on a mix of documentary, testimonial, and expert evidence:

• Copies of the POA, wills, deeds, and transaction records (bank statements, checks, wire transfers).
• Medical records and physician notes showing cognitive status near the time the POA was executed or transfers occurred.
• Testimony from family, caregivers, or witnesses about the principal’s mental state and the circumstances around execution and transfers.
• Expert opinions (e.g., geriatrician, neurologist, psychiatrist) to establish incapacity.
• Evidence of suspicious patterns (large or unusual transfers, sudden changes to estate plans, or transfers that benefited the agent disproportionately).

Common procedural paths and remedies

Which procedure you use depends on the facts:

• Civil lawsuit to set aside transfers: You may file a civil action seeking rescission of transfers, restitution, damages, and an accounting of the agent’s actions.
• Petition for removal of agent and accounting in probate court: If the POA was used in the context of an estate or conservatorship/guardianship, the probate court can remove the agent and order accountings.
• Guardianship or conservatorship: If the principal is now incapacitated, a guardian or conservator may be appointed to protect their interests and pursue recovery of misused assets.
• Criminal reporting: If theft, fraud, or elder exploitation is suspected, report to law enforcement and the Office of Adult Protection; criminal charges may follow.
• Temporary protective measures: Courts can issue temporary orders to freeze accounts or prevent further transfers while the dispute is resolved.

Timing and statute of limitations

Time matters. Different causes of action (fraud, conversion, breach of fiduciary duty) carry different limitation periods; some begin when the misconduct is discovered. Act promptly: preserve documents, take steps to stop further transfers, and consult an attorney quickly to avoid losing rights.

Practical steps to take now

1. Get a certified copy of the POA and any related estate documents.
2. Gather financial records showing the transfers (bank statements, transfers, cancelled checks).
3. Secure medical records or request medical releases that cover the date of the POA signing and the dates of the transfers.
4. Document observations: who was present, what was said, the principal’s ability to understand and communicate at the relevant times.
5. Contact the financial institutions involved to report concerns; ask if they can freeze suspicious transfers or provide records; banks often have procedures for suspected fraud involving POAs.
6. Report suspected elder financial abuse to the Office of Adult Protection (Idaho Department of Health & Welfare) and local law enforcement.
7. Consult an Idaho attorney experienced in elder law, probate, or civil litigation as soon as possible to discuss filing for relief and preserving claims.

Helpful hints

• Act quickly: evidence such as medical notes and eyewitness memories fade; banks may be able to preserve electronic records only for limited time.
• Don’t confront the agent alone if you suspect violent or aggressive behavior; involve an attorney or law enforcement when necessary.
• If the principal is still alive and lacks capacity, a petition for guardianship can both protect the principal and allow a representative to pursue recovery.
• Keep meticulous records of what you find—dates, dollar amounts, people involved, and copies of all documents.
• Financial institutions sometimes will reverse transactions if presented with evidence of fraud or incapacity; ask the bank about their procedures early.
• Consider a forensic accountant in complicated cases with multiple transfers or commingled funds.

Where to get help in Idaho

Start by consulting an attorney who handles elder law, probate, or civil fraud cases. You can also contact the Idaho Department of Health & Welfare, Office of Adult Protection to report suspected exploitation: Office of Adult Protection. For statute text and to learn more about Idaho probate and guardianship rules, review Idaho Code Title 15: Idaho Code, Title 15 (Probate and Trusts).