My client has a wife and 2 children who just emigrated to the US in July 2024. They got permanent residency status and social security numbers in July 2024. I will amend his tax returns for years 2021-2023 to change his status from single to MFJ. My question is: can I file 2 of his children as dependents for child tax credit (CTC) for years 2021-2023? He did support them financially when they were in Vietnam. 

I would not claim earn income tax credit (EITC) since they did not live with him in the US before July 2024. Is it correct?   

Thanks