Custody of aging parent. How can the oldest child get support to get custody of the father so he can have a stable home?

Ok, I am not reading this the way others are.

What I get out of this is not the children are the oldest daughters concern but the concern is for the brother. Seems he was living with his youngest daughter who has lost her home. This means another move for him.

Does the concern come from him having Dementia or health problems of some sort? Does the youngest have POA? If not, then why can't the oldest daughter just take him into her home? If he is competent than he can make decisions for himself. If not then the oldest daughter would need to get guardianship which overrides a POA.

Do your nieces not get along so they can work this out?

I don't wish to be cruel, far from it, but it seems the gist of the situation is that the father isn't able to provide proper care.   So perhaps the issue should focus on him, unless the oldest daughter is employed and/or old enough to take action to find support for the family.   How old is this daughter?

Does the father (your brother) work on a regular basis?  Have a profession?   Are there substance abuse problems in the family?  Has he ever been involved with governmental oversight before?  What were the results?

Grandma and MidKid offer good suggestions. 

The county health department might have to get involved, one way or the other, but at least to provide homes for the minor children.   

While I think this could challenge the bonds in the family, Child Protective Services may have to become involved to ensure safety of any minor children, who might be removed and placed in temporary governmental custody.

I think the issue focuses on your brother.    The oldest child gaining  custody over your brother may offer support for the other children, but specifically how could it help the father have a stable home if he hasn't been able to do so yet?  

I worked for the County Juvenile Court decades ago; while placement in a governmental setting wasn't ideal, it was better than allowing children to continue to be neglected when some parents just couldn't provide proper care or a home.  The children suffered, and it showed, resulting in these children needing psychological care.

I'm definitely not being critical, but I think all the issues of his parenting need to be addressed.  Your brother may be the one who needs county help more than the children.   But they do deserve the right to live in better conditions, and you're a kind person to try to find ways to support your brother and his family.

I have a dear friend who had to step in and get guardianship of her alcoholic father. It did take some time, and he didn't fight her, so it went as smoothly as I suppose something like this can go.

What are the ages of the children involved? That will make a difference. Does brother work or not? There's a lot to consider.

My friend said being her dad's guardian has brought her a level of peace, knowing he's safe and such--but also said it was massively depressing to have had to do such a thing for him. And this is one person. Basically, you're looking at a whole family. Is the OD ready for that? Maybe she's used to it.

No real advice--call Family Services and get a caseworker assigned, if they will do that. Be supportive to your niece and hope for the best.

If your brother is cognizant, has not been diagnosed with any form of dementia or mental illness then he does not need a Guardian.
If he has young children (under legal age 18 as far as I know) you could try to gain custody of children. But this would involve proving that he is unfit and involve a court decision.
If your brother does have dementia then the process would be to contact a lawyer and begin the process of gaining Guardianship.