Custom duty on used items while moving from Germany to India

Hello Friends,

One of my friends was living in Germany since last 3+ yrs. He had bought some household items, some electronic items and some items for his daughter (toys, Pram etc). Now he is coming back to India on 15th May. He had packed all his items in different boxes and sent them to India via DHL. DHL charged him 10K per box. Out of 10 boxes 2 reached Pune, India but customs have put a bill of 15K per box without any reason. He is now worried as still 8 more boxes are yet to be delivered. These all are used and old items still Customs have charged him. Is it valid? Is there any way we can question this? According to me if the items are used and more than 1 yr old, there should not be any custom duty. Please correct me if I am wrong.

Thank you..