Maybe part year resident returns for 3 states. Maybe just NY. Read up on the states rules for working in another location due to the pandemic. Will taxpayer return to NY?

Chances are, NY is going to tax it all.

Thanks.  From reading it is all NY state tax and nothing for the other states since the source is NY, or at least this is how I've read it so far.  Only part of NYC tax is applicable, again my reading, for the Jan-March time frame.  

This is about 10% of the information needed.  Did he own or rent in NYC?  Did he keep making mortgage or rent payments there?  Is he single or married?  Kids?  Where did the family live?  He finished the year in Utah -- is he still there?  Plan on staying?  Where did he register his car(s)?  Is he still driving around with a NY license?  Where did he vote?

yea you are right.  After posting I read more on NYC resident vs domicile, pandemic.  Still not sure on how to file this person.  Here is more info, any guidance is appreciated:

- she is single, no kids, no car (a couple years out of college)

- Rented and paid the rent in NYC until the lease was up on July 31, but moved out because office was closed to non-essential workers, due to pandemic.  Moved home to Massachusetts on 3/16/2020 until July 20.  Went to NYC to move out of the rental 1 day.

- Lived in Utah July 20 - current, voted in Utah

- Still has MA license (no car)

- Is planning on moving back to NYC in March 2021 IF all goes as planned (tbd)

- Has worked remotely for NYC firm since March 16, has not been back to office.

"Has worked remotely for NYC firm since March 16"

You are going to have to research how MA treats remote workers for income taxes, then. This assumes that paid time is on the W2, as well as the time in UT. You mentioned "worked from home" but that wasn't made clear that none of this is SE and all of it is on the W2?