My friend cant get his item back.

I was playing on the amsterdam (EU) server with my friend. We are level 14.
I got a unique robe that we could not trade. Probably because we are not lvl 25.
He dropped his unique weapon "The dark defiler rattling scepter" to check if we could trade. I could pick it up, but now I cant give it back again. It must be a bug, how can we fix so I can give him back HIS item?