I'm also sole beneficiary..And he had income from both places the month that he passed for 2015 as well. So 2014 retirement and ss not filed on yet and one month in 2015. Everything I'm reading sounds like I can file and receive the return. Please help! :)
IRD Income in respect to a decedent is what you are describing. Taxes are due on this income. Often when a decedent has a retirement plan the taxes in some cases can be greater than the estate tax (if any). File the individual Form 1040, assuming he is not a business owner and has a business entity tax return required. Sign as the tax preparer and give the IRS your contact info. The process is straightforward. Good luck on finalizing your dad's estate.
The safest thing to do is follow the instructions from the IRS. Use this link to help: