The courts did not disregard the questions surrounding Michael's living situation. They did recognize, under Florida law, the possibility of a conflict of interest. That is why it was the court that made the decision, not Michael. And again, I say simply because the courts arrived at a decision we do not like does not mean they didn't do their job.
It's not about "a decision we don't like", although we don't, it's about refusing to hear testimony on her behalf, it's about refusing to allow adequate unbiased medical tests, it's about connections with a sherrif who refused to investigate allegations of abuse, it's about a decision that is contrary to a specific provision of the State Constitution and now it's about defiance of a legal and binding federal subpoena.
How much does it take to call into question the soundness of one court's authority?
Yes, they did their job, but they arrived at the wrong conclusion. They are human beings, just like the rest of us.