SUBREDDIT: r/relationships
TITLE: How do I deal with this financial dispute with an old classmate?
POST: Non-romantic.

Two middle school classmates (28 F, 28 M) came to my city for skiing. We've known each other since 12, but hardly had any contact since high school graduation.

They stayed at my home for free for 5 days. In the last couple of days, the guy was feeling sick. I even cooked for him and bought all the food and groceries for them. They rented a car to go to the ski resort 1 hour from my city everyday. 

I went with them once (in their rental car). The other days I had work and went out to dinner with them a couple of times.

Now the guy sent me a bill expecting me to split the rental car fee evenly with them. 

I'm truly shocked because I felt that I was only being a good host. I didn't even have to go to the ski resort with them this time, as I have many friends and colleagues here whom I would go with. I only went to keep them company.

What would you do if this happened to you?
TL;DR: 
Do you think my old classmate is behaving ungratefully, or shall I pay up for the rental car that I didn't need?