I am not a reltive to the Soucy family. I did locate a very sparse obit for C. Fred Soucy. It does mention a surviving sister but even though I found her burial place, I could not locate her obituary in the Des Moines Register newspaper, as she passed away in 2003.
I will attach the obit for C. Fred Soucy. I did locate the obituaries for his parents but not sure if you want them or not.