Home ownership does not determine tax residency.
For tax purposes, CA regards someone as a CA resident if they are "present in California for other than a temporary or transitory purpose." You can find CA's complete rules on residency here:
https://www.ftb.ca.gov/forms/2021/2021-1031-publication.pdf
If the family member who moved to CA is there to stay, in the Personal Info section of TT he/she should enter CA as their State of Residence and indicate that they also lived in MD during the tax year. This will prompt the program to generate the correct tax forms for both states.
MD allows married couples who were domiciled in different states at year's end to file either MFJ or MFS. See page 4 of this MD tax reference:
https://www.marylandtaxes.gov/forms/22_forms/Resident_Booklet.pdf
**Answers are correct to the best of my ability but do not constitute tax or legal advice.
