My mom is fairly old and has been working, but recently has talked about retiring. She has saved a considerable sum of money. I am not located in the same City as my parent, but I have siblings that are. One sibling has been after me and my other siblings to convince us that my mom has dementia or alzheimers. I have insisted that it is not the case, since mom has continued to work into an advanced age. My concern is that this sibling desires to be placed as guardian for my parent, in order to get access to the money my mom has saved over the years. I never thought anything like this would happen in my family, but here it is. What is the process for having someone declared incompetent? My sibling works in long term care and knows all the social worker people around town, and could probalby get their cooperation if a doctor says she is incompetent. This is really scary to me, that my sibling could prevent my mom from coming to visit my family, keep her from seeing the grandkids, etc., and take all of mom's money. I just do not like it. Are there things I can do to protect my mom and myself?

I am sorry to hear that your sister wishes to have your mother declared mentally Incompetent and assume the Guardianship. After 2 years of being my husband's legal Guardian, I can say a Guardianship is difficult and expensive for all involved. It takes away your mother's legal rights to make ordinary decisions and worse leaves her vulnerable to becoming a Ward of the State, should the Courts deem that neither you nor your sister are capable of caring for her properly.
It is like the 'roach motel' easy to get into, but difficult/impossible to extricate and get out of. I would suggest that you get your mother to sign over Power of Atty to you or your sister. Also any directives such as a living will, while she is still legally competent. P of A retains her rights as a citizen and she can revoke them. Definitely have her write her Will while she is legally in sound mind. If she is declared MI, before this is done, it will be too late and her assets will be distributed by probate law/court. Probate of her Estate may not be according to her wishes. If you feel she IS incompetent, but don't trust your sister, Another suggestion would be to contact the Court and insist on being co-Guardian. That way you will maintain some control over all decisions. If you feel she is NOT incompetent, then get a doctor who is willing to testify that she is of sound mind before the Court. Also, be aware that the MI hearing is held first. You have a right to be there under State law and contest it. The MI must be made first before the Guardianship is assigned. You must decide what YOU want and act accordingly. If you know of any reason why your sister might not be trust worthy, you can bring that before the Court.
Personally, I try to discourage people from Guardianships. Does your sister realize how expensive and time consuming a Guardianship is? There are yearly bonding fees - based on the value of your mother's assets. In some States it's 10% of the value of the Wards assets - every year. There are annual reports which require copies of every check written and the figures must balance to the penny. The forms are difficult for the average person to decipher so you will have to pay a professional. The Guardian will have a Payee Acct which probably will include any SS payments. SS also requires annual accounts.
Although I am my husband's Guardian, it has turned our personal tragedy of a brain injury into a living nightmare. We have no financial privacy, I need Court approval to sell our home, move out of State. It is too late to write his Will, so our assets will be divided according to probate law, not according to his wishes, - should he pre-decease me. Discourage her if you can, fight the MI if she insists, and get your mother to do everything she can, before she looses her legal right to do so. You have my condolences.