I was at the ready for DD’s interviews. We actually started the interview together and said our greetings, then I left. DD called me into the room when the interviewer was ready for me. Some interviews had us log in separately on different devices and put me in a “waiting room” while they interviewed DD. (They told us this would be the format a few days beforehand).
I think it shows support and complete family interest if you are able to have at least one parent say a nice hello, even if they will not be asking/answering questions or become a large part of the interview.
Oh! And I almost always had sweatpants/yoga pants on with a nice sweater or blouse - and entered the room so that only my “interview” wear could be seen. LOL