What do you think of me telling my friend about an art show that he wasn't available to attend?
Why did your friend miss the art show?
Because he was too busy watching films on films.tv
Since your friend made the decision to skip the art show because he was watching movies online, it's perfectly acceptable for you to talk with him about what you saw there. Friends often tell other friends what is going on in their lives and it will be a good thing to catch up with your friend. Your friend may even decide to go to the art show himself after you explain what you saw there.
I'm going to make sure to tell him about the sucky art show. Not sure why he missed it.
Talking about the art show with your friend will be a good way to catch up with him.