TX
My brother-in-law moved in with my family recently due to financial constraints. He is going through a divorce and currently the arrangement is for him to have his kids every other week and they reside at our home during those weeks.
A court ordered social worker was assigned due to custody dispute and subsequently a visit was scheduled. The scheduled visit was during a time that I was out of town any my wife was not available and no expectation of our attendance was communicated by the social worker.
My teenage daughter was home at the time of the social workers visit and one of the questions during the interview had to do with living arrangement my brothers kids and bathrooms. An assumption was made by the social worker that the kids were sharing a bathroom so he proceeded to investigate this.
During his investigation, he came upon my daughters room/bathroom and entered alone with no parent present.
He than asked my daughter a series of questions pertaining to her personally as well as her take on my brothers children and dispositions.
I find this to be gross negligence on the social workers part for mainly 2 reasons:
1. Social Worker entered my daughters room/bathroom alone with her present and not adult present
2. Social Worker asked a series of questions to our daughter without parental consent
My concern is if I report this to the court or to the social workers manager; this would seriously prejudice or skew their report and effect the interview expectations that may be forthcoming for my spouse and I.
Even if another social worker was assigned, I fear they would not be unbiased due to whistle blowing.
Since the report is provided to the attorneys and findings will be in Open Records and brought up in court, I do not want to jeopardize my family's privacy or my brother-in-laws case by reporting this.
In any event, needs some feedback here.

You don't mention if any adult was there to allow them in the house. Was the brother in law there? They don't seem to need parental consent to ask questions

I see no reason to expect that you be consulted about the day and time of a visit. Social Services has your address as the address of your BIL and that's all they are concerned with. But you didn't really ask about that.

Regarding an adult present during a tour of the rooms and questioning of your daughter, I agree that that was improper. Unfortunately it's quite possible that your BIL told him to go through the house on his own, and any attempt to say otherwise has weakened it's credibility now. In other words, it was your BIL's responsibility to follow the social worker around the house, he easily could have, and he didn't.
I would let it go for the sake of the relationship with Social Services. And have a talk with your BIL. (He also should have told you when they were coming!)