Interview questions for identifying employer red flags?

Asking about working hours is likely to provide some useful information. e.g. "How often do people stay late at the office?" or "When was the last time that you had to stay late to fix something?".

Employers may not be completely honest with their answers, but if they value work-life balance, then the answer will probably reflect this.

In the last unsuccessful interview I went through, the interviewer mentioned something about "being a family" or similar.

I have major issues with this statement because it conveys a lot of unvoiced & unreasonable expectations or workplace dysfunctionality. It also seems that a lot of folks become really defensive when asked to explain what they mean by this and they try to pass it off as some sort of common decency and camaraderie when what they really mean is tolerating a lot of unprofessional conduct, extending a lot of undeserved and unreciprocated forgiveness, and forgoing duly deserved and legally owed recompense.

I am not a sex worker. Nor am I any sort of phycologist or psychiatrist. I also do not usually earn those sorts of wages. So I am absolutely 100% unwilling to pretend that anyone at work is related to me or engage in any of those things I described above.

Why did the person who was previously in my role leave? What's the average time someone is employed here? How many employees have kids? How old are the other employees? What's the usual vacation time someone actually takes here?

I probably wouldn't ask all of these, but a cross-section of them usually gives me an indication of how much churn they're having, the type of employees they have, and what the work style is

e.g. at a previous employer, asking "have you written your own in-house Perl ORM and Object Model?" would have saved me a lot of mental anguish and pain.