Even as a teacher of your students, you can sometimes make personal friends with them. My current graduate student (an adult of some 45 years) just confirmed per email that a hotel room in the desired hotel was booked and paid for me in advance. I will of course fully refund the amount after arrival. I have overseen the graduate studies of this student, and now I am the main supervisor of his PhD project hopefully to be terminated by July next year. I am doing this on a voluntary basis, and sometimes trying to be helpful and kind towards students in an exceptional situation is repaid in kindness and you are given so much back in return. Another great experience I would not want to miss.
You do have to be careful not to insult by insisting to refund that student. In any event it was good of him and just shows the value he places you in. Hope you can make a coffee in your room- will they give you a kettle?