Should I accept this inheritance for my grandson?

I am from a prominent, well off family. I married a woman from a similar family (Habsburg), but a foreigner. When Marie-Th�r�se married me, we renounced her father's inheritance and promised never to claim it. She was promised a huge monetary compensation, but never got it, and so the matter stayed. We had children, they grew up and had their own children. Meanwhile, my wife's parents died, and her only surviving half-brother, Charles, who inherited everything, died. He named my grandson, Philippe (his grand-nephew) his beneficiary. I am glad for Philippe, the inheritance is a rich one, and he is a nice boy and will look well after it. But the other relatives object. They say that since my wife refused everything, Philippe is not legible. If we accept, then, on his behalf, there will be a bitter fight. On the other hand, since Charles himself wanted Philippe to have it, it seems unwise to refuse. What should I do?