I’m still learning this myself. I’ve fired my own sister four times in four years, and I’ve also terminated my 14-year-old (not only because of what the money was being used for) but because I eventually had to admit I was tolerating behavior I wouldn’t have accepted from another employee.
The biggest question I’ve learned to ask is: “If this person weren’t family, what would I do?”
I don’t think the answer is becoming a cold, completely different person at work. I think it’s creating enough structure that decisions aren’t based on the relationship: written expectations, pay ranges, attendance policies, reviews, discipline, and consequences that apply to everyone.
I’ve also learned that flexibility without boundaries eventually becomes the expectation. Then when you finally enforce a boundary, you look like the one who changed.
An outside HR person could absolutely help create that structure and provide a neutral middle ground, especially around compensation and discipline.
I definitely haven’t mastered it, firing my sister four times is evidence of that. But I’m learning that sometimes protecting the family relationship means admitting that working together simply doesn’t work.