I am doing my elderly mother's 2020 taxes for her. She has lived in Pennsylvania for many years. In June 2020, she moved to live with my sister in Delaware. After 3 months (in early September), she decided to move back to Pennsylvania. Her income consists of pension, social security, and some investments.
Do I need to file part-year returns in both Delaware (3 months) and Pennsylvania (9 months)?
Thanks.
