For my parents and in-laws, we file using 1099R, then select the option that says "I need to file a substitute 1099R" and use form 4852 to explain that the pension is already taxed in Indian and due to the India-US tax treaty, they are not required to pay the tax here. I convert the pension amount from Indian rupees to USD using the current conversion rate and enter it in box 1 Gross distributions and enter 0 in the taxable amount and select code 7 for box 7.
