This is an old posting but maybe this will help. I too am related to George/Hannah, from Andrew Jackson, Samuel A.
I have a copy of the line from George M at Berkwick Upon Tweed. Getting down to George Jr it shows 4 sons. You may have seen this (from Kathy O'Connell). With all 4 sons gone I assume, the only way to find out more about Henry and Frank would be to trace their families. I assume both were born in Illinoise where your dad was born, Mercer County. The other brother Charles Joshua M was born in Hubbard, Hardin Co, IA, but is buried in Iowa Falls (Hardin Co)IA. I don't know how much you know about genealogy, but could try and find marriage records, etc, at the county seat in Eldora - they have always been very helpful - sounds funny to some, but check the phone books back as far as you can. Best searching! Andee