Who's been cashing those checks?

While trying to gather information to help my two brothers in their quest to emigrate from Venezuela to the U.S., I was told that they need copies of my late father’s early school records to serve as proof of his citizenship. I knew he had graduated at McAllen, Texas High School in 1949, so I wrote to the records department. They were able to trace his records back to elementary school in the late 1930s, and I am waiting to receive those. I was told that having his social security number might speed the process, so I contacted the local office and was informed that they needed a copy of his death certificate before they could release any information. While looking up his records, they discovered that his monthly checks were still being sent to his last address in Venezuela, even though he had been dead for more than seven years. Maybe the death certificate will clear things up, but I wonder who has been cashing his checks?