@4SV Namaste ---- thank you for your response ( answered my questions ).
Thus, your parents will file the 2023 return as Residents ( GreenCard Test ) but only as a part year resident i.e. residency beginning 5 th of Sept 2023. So for their 1040 form they will have to take itemized deduction, include all pension payments received post the entry date ( world income from that date onwards ) and be able to claim any taxes paid ( to India ) either as a post that date either as a deduction or as foreign tax credit. Please make sure the conversion factor used is as of the date of dep[osit in the bank in India.
Yes they would be subject to FBAR and may be FATCA.
If there is more I can do for you , please either add to this post or PM ( if the topic is not of interest to general users ).
Namaste ji and greetings to your parents
pk
