John:
Sure, the disks will "fit"! 3.5 inches is 3.5 inches! <g>
The Amiga has a utilitt called "CrossDOS". It's been included in the
Workbench from version 2.0 on. (It's also available as a commercial
program).
CrossDOS allows the Amiga to read and write to PC formated disks. Usually
the double-density jobbers. High-density if the Amiga has a high-density
drive. I have transported files between my Amiga and work PC for years.
The more important issue, though, is what is he transferring? Document
files? Graphics? If so, file format is important.
Nick