It makes no true difference what the original meaning of the native american word is. It would be hard to tell now anyway. The thought of a higher being, force or, mystery is what was meant. If it mis-translated into Great Father (which I do not doubt) it was so the concept could be understood. There is little doubt that the descendants learning of the 'original' language could be tainted over time and what was originally 'The Great Mystery' became 'The Great Father'. If it did or if it did not makes no difference today.