Adiyen’s mother had attained the eternal abode in a car accident while returning after worshipping Thirumogur Azhagar koil and Periazhwar thiruvarasu koil; aidyen’s brother does all the rituals and as her daughter what are the anushtanams should adiyen follow and what stotras can adiyen recite?

There is nothing much for a daughter to perform. As your brother is doing the required rites, you can help by participating in the rituals. There is no specific anushtanams for women as such.
You can also join in the annual obsequies; if you cannot join you can think about your mother on her shraddham day. You can recite all stotras. You can recite stotras like Daya Shatakam to overcome the grief due to the loss of your mother.