I filed 2010 for this client as MFS since he was estranged and not living with his spouse.

In 2011, 2012, and 2013 he filed as Single

I was contacted by a lawyer and asked if I could file his Estate tax returns as he had passed away in September 2014.  Was handed 50 pages of accounting and conservator documents to work with.

His Death Certificate lists him as Single.  However, in the documents I was given it shows that the Divorce request was only filed 2 weeks prior to his death in September 2014.

How do I file the final 1040?  The rules say to use the status at the time of his death, which would be MFS.  However, the Death Certificate is a legal documents (even if wrong).

Has anyone had to deal with something similar and advise me?