It would go on a 1041 estate return for the husband, but if thats all there is, I dont think theres any reason to file.

Was it a publicly traded partnership (PTP)?  Held in a brokerage account?  Was everything else in the brokerage account transferred to the widow or otherwise administered?  

Half the K-1s I see are for units held in an IRA -- are you sure it has his name and SSN, or is it under an IRA in his name, and the trustee's EIN?  And some inherited IRA's still have the name of the decedent on the top line.  

It appears that the widow did not know about the Partnership asset.  Was there an estate for her spouse?  Was she the sole beneficiary of the estate?  You have to determine who has a right of ownership to see who should receive this asset.  Technically, his lifetime tax obligations end at death and become the responsibility of his estate.  You have to ask a few questions.