The Social Security Death Index:
Mable Brooks, born 26 Sep 1902, died 2 March 1990, "last residence" in Ronan, MT. Her SSN: 517-48-3184 in Montana, in 1959.
The Montana Death Index:
Mabel B. Brooks, died 2 March 1990 in Lake County, Montana, identified as being widowed, no additional information.
I find five family trees having Mabel (Mabel Bell Collins):
= Owned by "CatherineShake" Identifies "Aunt" Mable, born 26 Sep 1902 in Wisconsin, living in Wisconsin in 1905, 1910, died as identified. She was married to Perry Eugene Brooks, born 1898 in Wisconsin, died 20 Oct 1976 in Ronan. No children identified. Shows a photo of her. I sent a message through the system for this person to read this thread. This person, if a niece, "might" have a copy of the obit.
-One owned by "rhind77367"
-One owned by "LanceMelton" shows a living son. He married Living Collins and had a son and daughter. Married Living Porch.
-One owned by "ArthurC1957"
-One owned by "dabuchholz" shows six sons and four daughters. No information on any of them.
Mabel is not listed, but her burial stone is shown with Perry's, also is a listing of children:http://www.findagrave.com/cgi-bin/fg.cgi?page=gr&GSln=br...
One of these children might also have the obit and other information. Not knowing what information you already have, I may have already found everything you already had.