We had the same thing happen to us in Paris when we were connecting to Budapest. They "assure"d us out baggage would be on the flight to Budapest (12 hours from time we landed in Paris to departure). Luggage was not in Budapest. We were on Uniworld river cruise. We filed a complaint at the airport. The next moring the cruise director was on the phone at 8:00 AM and demanded they find our bags (another couple's too from an Eastern country). For 10 days she badgered and berated the CDG airport baggage people but they said they were on strike and we'd have to wait. She then got the airlines involved and badgered them to give us more than the $50 for new clothes--she also told them we were expected to dress up in gown and tux (exaggerated but still had to dress up for dinner). I got my luggage on the last night on the ship, 10 minutes before going to the Captain's farewell dinner. We left the next morning by bus for Prague; my husband still didn't know where his bag was but was told it would be in our hotel room in Prague. It was not. The concierge didn't know anything about it but the manager did, as our cruise director informed them. About 5 PM, just 1 hour before the farewell dinner in Prague, his bag showed up. 10-1/2 days late !
On the first day, while everyone went on a city tour, we went shopping; the cruise director told us which shopping area to go to, and she called a "friend" taxi driver who took us there and told us the number to call him to pick us up. The cruise director told us we would get reimbiursed from the airline who last touched our tickets/baggage. She also was told that first morning to get what we needed and they'd reimburse us--just not go overboard with designer clothes/accessories. We were able to find a Marks and Spencer and bought pants each 2 pair, shirts, blouses, sweater for the very cold mornings, underwear, socks. We made it back to the ship with our bundles. I had to hem pants 6 inches. I used a 3 x 5 card as measurement, and somethng else I had that was an inch wide (belt I think), and got scissors from the desk and I had several sewing kits tp hem my pants. On the next portt stop I needed walking shoes, as did Bill, our local guide told us "that street", and we found a Footlocker where we got US sizes and shoes on sale.
Before we left Prague our cruise director gave us a letter on Uniworld letterhead, describing what we had been through and how long it took to get our bags. That became part of the claim. When we got home I called the airlines (Malev Airlines ) for procedure to file a claim. They couldn't have been nicer. I didn't have to use the trip insurance because we first had to file with the airlines. It took 2 months but on Christmas Eve that year, we got more than we provided receipts for; they told us they included pain and suffering, too. So, system works. Doesn't help your friend now, but our PD on the Unworld cruise handled everything for us when we were under her "care" . The most important thing, is to remain calm. My husband didn't for about 6 days, and I thought he'd have a heart attack. He did come on the tours, but didn't want to at first, he was just so angry. I thought, well, we did get some clothes, we can do undies every night, someone was working on our case, just enjoy. I didn't let it bother me, although I had to buy an additional sweater because it went down to 32 deg. ).
On several GCT cruises/tours, other people didn't get baggage and PD handled all the phone calls and tracking the bags for the GCT travelers.