"Yes, I believe Lizzie was his aunt. I have something written in dad's handwritting that states Lizzie, Jake, John, Phillip and Bill Pronk came to America and settled in Hospers, Iowa. the way is reads it leads one to beleive they were all from Holland. They were all from Henry Pronk that came from Holland. He also states there is another clan of Pronks-not from the same blood line living in this general area."
Lizzie might have been an aunt but it is also possible she was an aunt my her first marriage. At age 67 she was only married 22 years, so she got married at age 45. Another reason on to doubt that Lizzie was an aunt through blood is that she was born in New York, and the family came from New Hampshire.
I have a feeling the handwritten notes are wrong if in fact your Dad's name was Eugene Clarence Pronk born in Fulton Co, in 1920. It is not very likely that there was another Eugene Clarence Pronk we haven't found in the census forms yet, who was also born in Fulton Co, in 1920 from Dutch descent.