What Should I Do If My Sibling Is Trying To Contest My Parents' Will?

 Posted on April 17, 2026 in Estate Planning

Losing a parent is already difficult, and a dispute over their will can make that time even more stressful. If a sibling is trying to contest the will and you believe the challenge is unfounded, it can quickly lead to conflict and uncertainty about what happens next. If you are facing this situation in 2026, a San Antonio estate planning lawyer can help you understand your rights and what steps you can take before the dispute escalates further.

What Grounds Does Someone Need To Contest a Will in Texas?

A sibling can't challenge a will in probate simply because they're unhappy with what they received. Texas law requires a valid reason that meets certain standards. The legal grounds for contesting a will may include:

• Lack of testamentary capacity: The person who made the will didn't understand what they were signing or what they owned at the time.

• Undue influence: Someone pressured or manipulated your parent into changing the will in their favor.

• Fraud or forgery: The will was illegally altered, or the signature wasn’t genuine.

• Improper execution: The will wasn't signed or witnessed according to Texas law.

• Revocation by a later will: Courts will honor the more recent will if it’s legitimate.

Essentially, if you want to contest a will, you must prove one of two things: that there was a violation of the rules under the Estates Code Chapter 251 about who can create a valid will in the first place, or that something happened over the years since that would invalidate the will. 

Elderly adults are sometimes targeted specifically because cognitive decline can make it easier for someone to argue a lack of capacity. If your parent had dementia or another condition affecting their judgment near the time the will was signed, it’s likely to be cited in a will contest. 

What Steps Should You Take if Someone is Trying To Contest Your Parents’ Will?

If your sibling is unfairly trying to contest your parents' will, you need to begin building a defense immediately. An experienced attorney will guide you through these steps.

Gather and Preserve Documents

Start collecting anything that supports the validity of the will. This includes:

• The original will and any prior versions

• Medical records showing your parents' mental state around the time they signed

• Communications between your parents and their attorney

• Any estate planning documents, such as a Statutory Durable Power of Attorney, Medical Power of Attorney, or Directive to Physicians

These documents can be critical if the case moves toward litigation. If your parent worked with an attorney to create their will, contact that attorney. They may have copies of non-confidential files that you can use to strengthen your case.

Consider the Full Estate Plan

Look at other parts of the estate, such as trusts, transfer-on-death designations, or beneficiary designations on accounts that pass outside of the will entirely. A sibling contesting the will may not actually be able to touch those assets at all. Understanding the full picture of your parents' estate may help lower the stakes somewhat.

Watch for Signs of Breach of Fiduciary or Executor Duty

If a sibling was named as executor or was an agent under a Power of Attorney while your parent was alive, they had a legal duty to act in your parent’s interest, not their own. If they used that access to move money, change beneficiaries, or redirect assets before or after your parents' death, that may be a separate legal problem (called breach of fiduciary duty) worth discussing with an attorney.

Call a San Antonio, TX Estate Planning Lawyer Today

If your sibling is saying they’re going to challenge your parents' will, now is the time to get legal advice. Our San Antonio will contest attorney brings over 20 years of legal experience to elder law, guardianship, wills, trusts, and estate disputes throughout the San Antonio area. Call The Law Office of Ryan C. Moe, PLLC at 210-861-6000 today to schedule your initial consultation.