Notes:

Great Falls Tribune, Great Falls, Montana, Nov 1936
Great Falls Man Dies at Bonner of Heart Attack
William J. Lustgraaf, 47, well known in Great Falls, died suddenly Wednesday morning of a heart attack at Bonner near Missoula, according to advices received here. The body will arrive in Great Falls this evening and be taken to O'Conner Chapel.
Mr. Lustgraaf had made his home in Great Falls--819 7th Avenue North--for a number of years and was widely known. He was employed by Burch & Sons Contractors and was working on a bridge construction job at Bonner at the time of his death, having been at the place for about the last three months.
The family came to Great Falls a number of years ago from Rudyard. There survives the widow and six children, Mary Lustgraaf, who had been at Bonner with her father, Helen, Margaret, Edward, John and Martin Lustgraaf, all of Great Falls.

https://www.findagrave.com/memorial/8559245/william-john-lustgraaf

William married Louise V. Mikulecky. Louise was born 5 Aug 1895, Rice Lake, Barron County, Wisconsin, USA; died 19 Sep 1992, Great Falls, Cascade County, Montana, USA; was buried , Mount Olivet Cemetery Great Falls, Cascade County, Montana, USA. [Group Sheet]

Notes:

https://www.findagrave.com/memorial/8559242/louise-v_-lustgraaf

Louise V. Lustgraaf, 97, 819 7th Avenue North, who worked at the Great Falls clinic for many years, died of natural causes Saturday in a local nursing home.
She was born to Wencil Mikulecky & Aloisia Rousar, 5 Aug 1895, in Rice Lake, Barron County, Wisc., where she attended schools.
She married William J. Lustgraaf in Great Falls 20 July 1912. He died in 1936.
She retired from the Great Falls Clinic in 1957 where she had been a custodian.
Children: Mary (Earl) Tanner; Helen (Roy)Shikany and Margaret (Bernard) Sweeney; sons, Edward (Gladys) Lustgraf, Martin (Hazel) Lustgraaf, and John (Jacquelane) Lustgraaf.