Hello c:
Ooo fun! What languages?
To be fair, it's fun to learn different languages so that you can explore the world and be able to interact with others more proficiently. I personally think traveling to other countries would be very fun and each one would be a unique experience. Not to mention, it will help you land some jobs, which is nice. Also, learning a language is entertaining and a fun challenge for some people. I, myself, could never learn more languages - it's too difficult for me, although it would be fun to know more.
Anyhow, you may think it's silly or stupid, but it's his life and that's what he wants to do :)