tracing children of Robert Ezekiel Parker and Ella Farley Dixon

We have been able to trace our Parker heritage all the way back to Samuel Parker born in 1612, but have not been able to find out what became of two of my Father-in-law's siblings.  One is Pearl Parker, born in Kentucky in Sept. 1897.  The other is Joner Earl Parker, born in Kentucky in Oct. 1899.  We can trace Pearl to Illinois in 1910 and Joner to Iowa in 1920.