How to get my mom declared an incompetent witness to not engage in a legal deposition or trial for her personal injury case?

Dollie,

I'm pulling your quote out of the "reply to" section and mainstreaming it; it's just so much more efficient to follow posts that way.  

You wrote:

"In the end, her lawyer said the defendants have a legal right to dipose the plaintiff and that my mom is not declared legally incompetent by a judge (not yet anyway) this is what I am looking into."

I haven't read court rules in decades, but that's probably true.   However, an attorney does need to factor into the dynamics the care and welfare of his client (your mother), and if a doctor will concede that it  could be not only confusing but distressing and harmful, that letter could be shared with defense counsel.  

I don't have access to online tools to check for case law on this issue, but attorneys do.  

Did some quick checking though and found some interesting hits:

https://www.google.com/search?ei=LOvzXdrpGJaltQbK4IHIBw&q=plaintiff%2C+testimony+of+dementia+paitents+++&oq=plaintiff%2C+testimony+of+dementia+paitents+++&gs_l=psy-ab.12...517470.530713..533967...4.0..0.142.4577.47j7......0....1..gws-wiz.......0i7i30j0i13j0i7i10i30j0i8i7i10i30j0i8i7i30j0i13i30j0i13i10i30j0i30j0i8i30j33i10j33i10i299.Ok_3OgWMQjI&ved=0ahUKEwjar9m5srPmAhWWUs0KHUpwAHkQ4dUDCAo#spf=1576267076246

This was one of the hits:

https://gartenlaw.com/articles-of-interest/deposing-an-incapacitated-person/

However, it's primarily Florida case law.

Rosered6, a guardian ad litem does differ from a Next Friend, at least in Michigan.    To the best of my recollection (as I haven't worked on these kinds of suits for decades), the NF is appointed only for a specific purpose in litigation.  As indicated, it was usually when a youngster needed an adult to "stand in his/her place" in litigation, often personal injury suits.   The youngster can't represent him/herself, so an adult (parent usually) "stood" in the child's place for the purpose of the litigation.

This is a good explanation of a Next Friend:

https://www.law.cornell.edu/wex/next_friend

There may be other broader uses but I'm not familiar with them.    A GAL has broader powers overall.

I have some vague recollection of GALs being involved when I worked for the Juvenile Court, but those memories (other than the horrors of the neglect situations) have mostly faded.

In my state, a guardian ad litem (probably equivalent to the "next friend" referred to by Garden Artist) can be appointed for an incompetent person for court proceedings, including personal injury suits. Ask your mom's lawyer about this possibility.

The word is "depose," meaning to ask questions of a person at a deposition.

Dollie, I have never heard the word 'dipose', and it doesn't register on Google. If it was a mistype for 'dispose' it still doesn't make much sense. The defendants certainly can't 'dispose OF the plaintiff'. Ask some more questions.

Dollie, I assume your mother is the Plaintiff, i.e., the one who initiated the suit?   If so:

1.   Contact her attorney and explain the situation.  It's to her/his advantage as well not to have your mother testify.

2.    Ask about amending pleadings to create  "Next Friend" suit, i.e., you act as Next Friend on behalf of your mother, who's no longer capable of testifying.   I've only worked on these when parents have acted on behalf of young children, so I don't know if this is applicable or allowable under the local court rules where the suit was filed.

3.    Work with the attorney on obtaining medical records, although I'm sure they're already available.  That's one of the first tasks plaintiff attorneys undertake.   

4.    Ask also about getting updated medical records, especially from your mother's neurologist, to support a dementia diagnosis; defense counsel will likely demand that if your mother is to avoid deps and/or trial testimony.

I think you're wise to address this issue now.    Your attorney may recommend a settlement to avoid prolonging the litigation.    Many personal injury suits are settled out of court anyway, unless the attorneys are the tv attorneys who advertise and brag about their massively huge settlements.   

If so, you would also have to sign the Release forms on behalf of your mother.   Check the wording in the DPOA/POA to ensure that it allows you to do this.   And think about handling deposit of the check if you don't already have joint privileges on a checking account.

If this was "diagnosed verbally" it may be in the doctor's notes. You can call her doc (if your mom has signed the Medical Information Release form naming you as a representative) and ask the doc if this info made it into the notes. If so you can request a copy of these notes and present them to your attorney if you need proof. If there is nothing in the notes, and your mom is resistant to going in for a cognitive test you can make an appointment (with even her GP) and tell her it's for something else and pass the doc a note requesting a cognitive test and also test for UTI, and they will do this. Then, if she has decline of any sort, it will be recorded officially. You could also tell a "therapeutic fib" to your mom that the court or attorneys are requiring a cognitive test before the deposition. FYI having durable PoA does not allow her doctors to discuss any of her medical info with you, she must sign that paper and name you on it. Ask for one at each of her of doctors' offices. Best of luck to you and your mom!

Her lawyer should handle this sympathetically - isn't s/he doing? Or is it that your mother is pawing the ground, keen to get in there and sock it to them, only she doesn't realise how hard it could get?

Contact the attorney handling the case, ask them how to handle it. Does mom remember anything about the incident? You may not have a choice.

You could request the case be dropped, but then attorney fees would probably be charged to mom. But, better now before depositions and attorney court time. How long ago was this? Did mom file the suit?