A friend had to pay with his credit card, make the booking, and I had to pay him cash back.....Why would I be expected to pay many times the cost of the original ticket, in additional fees, to correct an error they had transcribed?
Ryanair does not "transcribe" or change names willy-nilly. It's quite obvious that your friend typed "Jim" when he was booking on your behalf and that's what appeared in the booking.