A disinherited sibling can challenge a California will, but usually only on specific legal grounds. In most cases, that means lack of capacity, undue influence, fraud or problems with how the deceased signed the will.
Unfair treatment alone is not enough
A parent can generally leave property to one child or sibling and leave another out. A will contest usually turns on whether someone did something legally wrong with the document or the circumstances around it.
A disinherited sibling may have grounds to challenge the will if the evidence shows:
- The person who made the will lacked mental capacity.
- Someone used undue influence or pressure.
- Fraud affected the will.
- Someone did not sign the will properly.
These issues matter more than whether the terms of the will just feel unequal or unexpected.
California probate deadlines can limit a will contest
California gives interested persons a limited time to challenge probate, and a person usually must file a petition to revoke probate within 120 days after the court admits the will under the time limit for revoking probate. That can matter when a family discovers suspicious changes, a sudden exclusion or signs that another person controlled the process near the end of the deceased’s life.
A will contest depends on the available evidence
A sibling who did not receive an expected inheritance will need more than family suspicion or hurt feelings to proceed with a will contest. Medical records, prior estate plans, witness accounts and facts about how someone prepared the will may shape whether the claim can succeed. A will contest may also affect how the estate moves forward during a dispute, including control of assets and the probate timeline. A lawyer can help assess the evidence early, before the filing window closes or key records become harder to obtain.