My brother passed before signing his will. How and where do I go to be appointed as his representative?

My brother has no spouse, no living parents, and 4 siblings. I had his POA. I filed his income tax and he is due a refund, but I have been told by the IRS that I need to file Form 56 before they will talk to me. He also has a small 401K that he did not name a beneficiary for—I have spoken to them & been told that I need a court appointment as his representative. Do I go to a court in Travis county where he lived or can I file in the county that I live in, which is Smith county. The money is less than $7k and will be used for his burial expenses.