2nd time to be towed by the ADAC

Hello, yesterday I had to be towed from the ADAC from the motorway to a nearby parking lot to get the car from the highway. Since it was not my vehicle and the owner is not reachable, I did not know of course what should happen now with the car. The car is now there in the parking lot. However, the owner would like to have the car transported back to his home (ADAC Plus membership). According to the ADAC employee of the then Tow, tow is only free the first time. Is that right? For me, the first towing is part of the granted breakdown aid and the second tow would be the vehicle return?! And if it didn’t work out at all, what do you think, if I would tow the car myself on the road and then call the ADAC wg. a new (old) case…?!