The only way to become executor would be to  file legal action against your brother and the estate in chancery court (a part or division of county court) accusing him of violating his responsibilities as executor and asking the court to replace him with you as exector. Unfortunately, only a court has the authority to change executors, add executors (or to order an executor to do something which he should do, but has not--that is alternately something else you could ask for in the legal action), so a lawsuit is the only way to proceed. Because of the short time frame you describe, you would have to apply to the court on an "emergent" (think: "emergency" or "urgent") basis to get into court in a few weeks, instead of several months. Note that a chancery court action in regards to an estate or executor is complex, and applying on an emergent basis increases the complexity--this will be a complicated case to bring without an attorney, but hiring a lawyer could cost more than the policy is worth.