Building with lego I think it teaches lessons for life, it may take effort to put them together and take them apart but the achievement is very good. It reminded me of when I was a child and I had the predecessors of lego, they were made of rubber. I liked to build houses, buildings, cities...
Soon you will have your nephew enjoying himself there, that's great!!!
Yeah, amazing to think Lego was invented back in 1932 and is still going strong.
And I think it will go on for a long time. It's more than a game.