I have a work visa taxpayer who lived in US until October 2020; spouse and US born children living outside US for all of 2020.  Prior 4 years all lving in US and filing as residents.  Taxpayer and family will not be returning to US for next few years at least. For 2020 Should I file MFJ return as if all were residents?  Would taxpayer be considered Dual-Status alien? What, if any other considerations or impacts should I be making?

Thank you for any direction.