2018 Nissan Sentra SR Brake stuck, wouldn't start

That likely indicates a failure of the vacuum system and is likely due to a vacuum leak or a failing booster. When you shut off the engine, the vacuum system retains negative pressure in reserve for future starts, so the peddle can be easily depressed with the engine not yet running and the fully depressed brake peddle can signal this to the computer and the car will be allowed to start. Without the peddle depressed, this signal isn't being sent and the engine cannot start..... All this could also be caused by a battery that's so bad that it can't provide enough juice to power this function.

Sounds like he's talking about the battery in the fob. On many vehicles the fob must be near the vehicle for the vehicle to start. If the battery in the fob is weak or dead it won't be transmitting and the computer will not allow the vehicle to be started. Hope that helps! Jim