I also have this information. I have copies of Avery's application for SS so I have parents names. I have looked in friendship as that is about where Chet and Frieda lived.
Last known address was in IL. Annabel had given me names of brothers and sisters of Avery, and I am finding some of them. But everyone's memory is bad, cause nobody remembers much. Which is really frustrating. the 1940 census will be released in 2010. Every ten years. There were 6 brothers and sisters. Not all stayed in WI. on grandpa' app. he has his mothers name listed as May Chase, Not the Mary that seems to be listed on everything else. I do believe I know who you are, your brother would be Paul. Your dad was Bob.
Your Mom is my aunt. If you want to know anything that I might have already, I'd be glad to share.