If he's got a terminal app on that apple 2 that might be the best way to do it. Fire up hyperterm on the pc and do an xmodem transfer. Any other solution would probably require you to buy something.
If theres a tape deck, you could move the file to the tape, then play the tape in a tape player hooked up to a pc sound card, there are apps for converting the audio data back into the original file on the pc.
You could write a little basic program to move the file over the serial port, and use qbasic on the pc to capture the data.
If i remember, you can get into the basic intrepreter on the old apple 2 whatever machines by rapidly flipping the power switch.