Camshaft adjustment

HI ALL, HI BOESER SIETER (if you still exist here) There is a problem again with which I am sure many can help, and hopefully also want to. My brother bought a 200 compressor W170 MOPF last week in Austria (he is richer and lives there too). At the sale was the ABS lamp on, but the seller could convince my brother that it is nothing bad, and so he bought. Against my foreign advice, because I would never buy a car where I could buy a car. When the disease has once penetrated into these new cars, everything can happen. Yesterday the first drive from Upper Austria to Bavaria to work, at Deggendorf the engine control light goes on. With Mercedes everything is read out, the valve to the camshaft control is leaking, the oil pushes into the motor cable tree which also needs to be changed, the steering gear is not affected yet. The error message came from the lam bdasonde, he sounds too fat. I would now have the following questions: Could the seller temporarily “still” the engine control light so that it doesn’t kill the sale? That would then be a messy touch, one could legally do something for sure. At least achieve a return. Is the damage to the car common or frequent with the model? Is this a rather harmless repair that keeps itself in price limits, so car keep and repair, and good is it! Do you know about the case? Many thanks for the numerous inscriptions in advance.