Fantastic city, he will love it. The gaudi architecture is beautiful. Just wandering around is great. There's las rambles and the gothic quarter, npmany beautiful churches. For an interesting food experience visit la boqueria market, looks amazing and the little tapas bars are a real treat, great food. If he has a day to spare a trip to Montserrat is amazing. There are often great concerts on, so worth him checking. And the Catalan art art gallery and the science museum are good.
A friend of mine from the USA is going to Barcelona for a week for work. He's currently booked to stay at the Barcelona Centre hotel and he's asked me if i have any knowledge of the place, any tips of good places to see, do, visit, eat in etc while he's there.
I've never been so i thought I'd ask you guys if you have anything you'd say specifically about Barcelona.