[FL] Can we address lengthy bathroom breaks?

We work in a very small company with less than 10 people. We have one single male and one single female restroom. We have one employee who spends 15 minutes in the restroom every single time, 5 times a day, exact same times each day. We all know this because the restrooms are located right outside our office doors in shared hallway. This makes it so others cannot use restroom, and he's spending more than an hour a day in there essentially wasting time. Sometimes he goes in and flushes the toilet in one minute, and still stays for another 10+ minutes, no additional flushes. The owner of the company is frustrated, but doesn't know if anything can be said to address this. We do not have an HR department. Looking how we can phrase this, if at all. No medical accommodations have been asked for nor discussed.