Plenty of touring bikes use Deore bits too, as most iterations have been decent, reliable and value for money and offer some different cassette ratios. If I were you/him, I'd ride it and replace bits as he breaks them, they wear out or he realises they don't suit what he wants.
Obviously, it's all personal taste. And I quite like the slightly franken-nature of mixed up groups anyway (see the functional and frankenbike threads also for some ideas). So matchy-matchy isn't really a thing for me. But it's his. Do what it takes to get your mate riding it and then enjoy it!