@Emmy21
You can spend a lot of time and energy trying to get money from a guest for relatively small damages. If you involve AirBnB they will want proof from you that the guest did the damage. Do you have admission from him on the AirBnB platform? If not, then you will find it very difficult to get AirBnB to rule in your favour.
Personallly for a small item like this (unless it was a very expensive bar stool) I would leave it be and put it down as a cost of doing business.
We put a small amount aside from every booking to cover accidental damage - we also have host insurance in place which is much easier to claim on than via AirBnB's host cover etc
Good luck