I have a friend who has a car with leather. But I don’t know if it’s real or not. In this case, do I have to consider my friend’s car as najis? There’s a huge probability that it indeed contains real leather (most of today’s car contain a mix of real & fake), however since I don’t have a confirmation from the manufacturer that his car contains real leather, can I religiously consider the car as pure?

You can consider that it is not real leather.