A lot of airlines have no-show fees, it'd be in the fare rules if you pull them up on Experflyer, etc. Not sure your friend's itinerary and fare class, but this is just something random I pulled up, imagine it's pretty standard on PR's international tickets. Bolding added by me.
PENALTIES
CANCELLATIONS
BEFORE DEPARTURE
CANCELLATIONS PERMITTED.
CHILD/INFANT DISCOUNTS APPLY.
NOTE - TEXT BELOW NOT VALIDATED FOR AUTOPRICING.
SUBJECT TO USD 50 REFUND SERVICE FEE.
-------------------------------------------------
NO SHOW FEE USD 75 APPLIES FOR CONFIRMED BOOKINGS
NOT CANCELLED 24 HOURS PRIOR ORIGINAL FLIGHT
DEPARTURE.
AFTER DEPARTURE
TICKET IS NON-REFUNDABLE.
CHILD/INFANT DISCOUNTS APPLY.
CHANGES
ANY TIME
CHANGES PERMITTED.
CHILD/INFANT DISCOUNTS APPLY.
NOTE - TEXT BELOW NOT VALIDATED FOR AUTOPRICING.
CHANGE FEE USD 50
--------------------------------------------------
CHANGE FEE TO BE COLLECTED PER TRANSACTION FOR
REBOOKING/REROUTING/UPGRADING OR ANY CHANGE
REQUIRING TICKET TO BE REISSUED.
--------------------------------------------------
FOR PARTIALLY USED TICKET THE ORIGINAL
NONREFUNDABLE AMOUNT REMAINS NONREFUNDABLE
AT ALL TIMES IN CASE OF UPGRADING.
-------------------------------------------------
NO SHOW FEE USD 75 APPLIES FOR CONFIRMED BOOKINGS
NOT CANCELLED 24 HOURS PRIOR ORIGINAL FLIGHT
DEPARTURE.
BTW, This used to be a lot cleaner to insert into a thread. Looks like some of the old tools are missing now.