Where is the fuel sensor?

Jennifer,
Yes, that helps. The THROTTLE POSITION SENSOR is a black plastic device [abbreviation is TPS] mounted on the throttle body. It is held on with 2 screws and has a 3 wire electrical harness plugged into it. The easy way to locate the throttle body [in case your brother does not know] is to follow the black rubber tube which goes from the air cleaner to the engine. the aluminum device that rubber tube connects to, is the throttle body. There is another sensor called the IAC [Idle Air Control Valve] which also is attached to the throttle body. The IAC usually has 4 wires, rather than 3, going to it. That is the easiest way to differentiate it from the TPS [Throttle Position Sensor]
The TPS can be changed by unplugging the wiring connector and removing the two mounting screws. To further complicate the issue, Ford used two styles of TPS. One style has slotted holes for the two mounting screws. The slots are designed to allow the sensor to be adjusted. The second TPS design does not have slotted mounting holes in it. It can only go on one way, and is NOT adjustable. If your car has the style with slotted holes, you will need to use a computer scanner to read the voltage of that sensor [with the key on, engine off and gas pedal [aka throttle pedal] at idle. If the voltage for the TPS is between 0.9 and 1.1 volts, everything is OK. If the voltage is not within that tolerance, you must loosen the mounting screws and move the sensor in the slotted holes, to get the proper voltage reading.
If this is all to confusing for your brother, you will need to take the car to a professional mechanic.
Does your brother know if your engine has throttle body fuel injection or four individual fuel injectors? I ask, because that also makes a difference.