Artwork for ETH

So i am a total novice when it comes to cryptocoins, i only know the technical side of it. My Father Was offered 5ETHs for one of his Artworks (Hes almost 70 years old and his artworks stell normally for about 10.000€) So my question are: 1. Does this Sound like a serious Koffer to you, or is it a scammer? (expecting a pricedrop or something? 2. If we would accept the offer, how do I pull this of? How to gain the coins savely? And how to sell them, or store them? (we are sitting in Europe and the buyer is american… Maybe it makes a difference)

Thanks in advance!