I was asked with my daughter in law who is sunni, that she believe panjatan 5 are infallible a.s but what about the rest till Imam Mahdi A.J.F who chose them to be Imam or get imaamat. I want you to answer her with references please.

Kindly refer to the link below for detailed answer to your very important question

https://www.al-islam.org/shia-rebuts-sayyid-rida-husayni-nasab/question-6-why-do-you-regard-your-imams-as-infallible-masum

https://www.imamreza.net/old/eng/imamreza.php?id=13163