Losing a loved one can be devastating, especially if they were living with dementia and their personality changed toward the end of their life. It can be even more upsetting to find that they made a will to disinherit an immediate family member.

The good news is that you’d have ample opportunity to fight the will and several different legal arguments you could make to preserve your mom's inheritance. Here's what you need to know.

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You can contest the second will

As a general rule, if someone makes a second will, it will invalidate the first one. But that's true only if the second will is valid — which may not be the case if your father had dementia at the time he created it.

"If your loved one has created a will and they have been diagnosed with dementia, then there may be grounds for contesting the will," advised Derek Jacques, attorney and owner of The Mitten Law Firm in Detroit in an email interview.

"Wills created by those with a medical diagnosis will be scrutinized more heavily by probate courts anyway, and if there is something uncharacteristic in the will, it can be contested by a party with standing."

Of course, this doesn't always mean you'll have a slam dunk case.

"The capacity for making a will does not disappear simply because someone has dementia," said Evan Farr, founding elder law attorney at Farr Law Firm in a separate e-interview. Farr explained that you'd need "strong proof that the person with dementia did not have sufficient capacity to sign a will."

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Proving a will as invalid

If you or your mother were to contest the will, the burden would be on you to prove it should be invalidated. Jaclyn Roberson, senior partner at Roberson Duran Law, PLLC echoed this reality in a third email interview.

"If someone wants to contest a will, they would likely need to provide documentation such as medical records, witness testimony or other evidence that would prove the testator lacked capacity at the time they executed their will," she explained. "Whether the will would be ruled invalid will depend on the strength of the evidence presented in court."

At this point, if you succeed in convincing the court that the second will is invalid, then the prior will should apply as long as there is no reason to doubt its validity. If there was a problem with the first will, then intestacy laws would determine who inherits what. In a successful case, your mother should receive the entire estate, unless your father had other children outside of the marriage, in which case the estate could be shared.

You often can't disinherit a spouse

Even if the second will was valid, the good news is that your mom may still have some options.

"Most jurisdictions have several guidelines and laws in place that make it very difficult for one spouse to disinherit another," Jacques said. The specific rules can vary depending on where you live.

"In any community property state, property acquired during the course of a marriage is joint property and the surviving spouse has a claim to at least half the property. In other states, spouses can claim an "elective share" or "statutory share" of the deceased spouse's estate,” said Jacques. “This share is usually a fixed percentage — often one-third or one-half of the estate, regardless of what the will says. The spouse must file a claim in probate court to receive this share."

This means your mother should be able to claim at least part of the property left behind unless there was a prenuptial agreement or other similar agreement in place between the two specifying otherwise.

Since court action may be needed either way, it would be a good idea for you and your mother to talk with an estate planning lawyer to see what your options would be. The good news is that you'll likely find multiple ways to regain possession of your dad's property for your mother so she can have more security in her later years.

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This article provides information only and should not be construed as advice. It is provided without warranty of any kind.