AIO to my employee calling in sick?

I own a very small salon with 3 employees. 2 of them are part time and one is full time. The full time employee is also a family member. Over the course of two years the salons been open , my family member has called in fairly frequently (in my eyes).
This year so far she has canceled 1-2 days at a time 5 of the 7 months. I had a conversation with her that went poorly. She said she can’t help how often she calls in because she had the norovirus, the flu, a stomach bug, and a bad cold and trouble with some medications that made her feel bad. It seems like a lot of times being sick in one year (to me).
The problem is, I don’t believe her. She almost always calls in after a weekend of partying. She lies about the partying and always says she is sick when she calls in. But because we are related, I know that she was out the weekend before each incident. Alcohol causes her a lot of anxiety and she then needs time to recover. It has become such a pattern that on the 4th of July she got pretty drunk and I joked with my husband that I hope she doesn’t call in sick afterwards. Well, sure enough, she works one day, then the next day she cancels her appointments and tells me she has a uti and had to go to the doctor.
So she has called in sick Jan, Feb, March, May, July. All for claimed illness but I don’t know if I can trust her.
Beyond that, I’m not sure if I’m over reacting because to me calling in every month to every other month seems like a lot. Especially when you are disappointing clients who probably take off work and plan their days around their hair appointments. My reputation is on the line and I don’t want to be known as the flaky salon. On the other hand, I don’t want to be an unreasonable boss who is letting my personal bias get in the way. So AIO? Is calling in sick that often too much? Or should I mind my business and let her take time off as needed.