Palmer says he is Lakota, Cherokee, and Choctaw. He also runs Oyate Music, which claims to be the only Native owned and operated label. (That's not true, there are several NDN owned labels I can name off the top of my head.) But even so, they do put out quite a bit of music by NDNs.
I couldn't find any evidence of any complaints he is not what he says he is. Could you tell us why you believe he is lying?