Thank you for the prompt reply to my post. I have Joseph and Rachel's wedding record saved to my ancestry.com tree. Most of the online references to the family list Robert as being Joseph's son, but DAR requires "proof". I seem to recall reading an article that mentioned Robert being in business in Texas with his brothers Greenberry and Joseph. I will look for that again. I'm also trying to find if Robert had an obituary posted when he died in 1880. Will also look to see if his brothers or sister Hannah Harrison Johnson had obituaries that might have mentioned brothers.
I think eventually I will come across some definite "proof". Thanks again! Terri