@Terry53029 I think in his case he does not need to file form 8833 because he can "claim a reduction or modification of taxation of income under an International Social Security Agreement or a Diplomatic or Consular Agreement." Which in his case there is an agreement between the Australia and US.

Yes, that worked. I did adjust his self-employment tax on SE adjustment worksheet and include in the statement explanation of the Agreement. So, the next step is to finish complete 1116 and 2555?