grandmother (indian) adopted by Duvall's

My grandmothers name is Ida Edith. She was adopted by the Duvall's.She was adopted in Oklhoma and married T.M. Kirk they had a son Leo.According to indian record they lived on the land and Ida and her son are both enrollrd to the tribe.I am looking for any info because I have a rare blood cancer that may be linked to my family.