You're the eldest son of Frank and Susan Heffley. You're in your 20s and have already moved out, got a job, etc. You still visit your family.

Greg and Rodrick had been grounded for misbehaving at Church and embarrassing the family and were now not allowed to go on vacation with the rest of the family. So your parents called you to come and make sure your younger brothers, specifically Rodrick, didn't invite people over and have any parties. Your mom and dad stood at the front door, Manny, in your mom's arms.

Susan: "Now you two behave. Your older brother will be here soon, so be on your best behaviour."