The sword that was taken from Wadu should be returned to his family at the village of Lhanuch, in Nan Laeglin.
'It is no use dwelling upon such mysteries, for we may never know the answers to them. He spoke of his family to you, did he not? They must be told of his death, and the sword returned to them.
'You will likely find them at Lhanuch, the village of the Uch-lûth, in Nan Laeglin. You should ask the people there until you find his father and bring him both the unhappy news and the sword.
'It may seem cold, but perhaps the death of his son at the hands of another Dunlending clan will soften the father's heart to the Dúnedain. Wadu may still help us in our errand, though he be slain.'
Wadu's father Suvulch can be found somewhere within the Uch-lûth village of Lhanuch.
You need to find the father of Wadu and bring him the sad news of his son's death. Additionally, he should be given the ancient sword of the Rohirrim that was taken from Wadu when he was slain.
Wadu's sister Nona can be found somewhere within Lhanuch, the village of the Uch-lûth, in Nan Laeglin.
Suvulch has coldly dismissed the death of his son Wadu, calling him a coward. You should bring the news of Wadu's death and the ancient Rohirrim sword to his sister Nona instead.