It all depends if you're talking about just a "Get to know each other" meeting; or an interview. MOST of the applicants I had, I arranged meetings with before the actual interview. Sometimes, because of distance, we'd simply chat on the phone for an hour or so. I'd answer questions about the academy, about the process, about academy/air force life, backup plans, etc. I had no problems with parents being there and asking their own questions. Matter of fact, most of the time if we were going to meet, I'd go to their house. I didn't mind mom, dad, sister mary, or brother john asking questions.
Now, the interview, that's a totally different story. It's not a matter of SHOULD a parent or SHOULDN'T a parent. I was quite clear.... The parent IS NOT ALLOWED to be anywhere near me and little bobby/susie during the interview. I've had a couple of parents ask why not; and even be a little persistent about it. My answer is quite simple. If they want to sit in an academy interview, then THEY can apply to the academy.
I say this generically. As Flieger will testify to, each ALO has their own way of doing things. Some are very involved with the applicants; (Flieger); some aren't so involved. Some use the meetings and interview also as mentoring moments where the give advice to the applicant on how to do the application, how to interview with the MOC, etc. Me personally; I don't want applicants coming to my interview dressed up in ties, dresses, suits, etc. I tell them specifically that I don't want it. I do this for numerous reasons. 1) Will they follow my instructions, or listen to others saying they need to dress up. 2) I want them relaxed so I can get to know the REAL applicant. Not a bunch of canned memorized interview answers.
Anyway, each ALO is different. I'd recommend asking you son/daughter/applicant to check with their ALO. If it's just a get to know each other meeting, have your child ask if mom/dad can come too because you have some questions and would like to know more. Especially about supporting and assisting your child where you can. Most ALO's like parents who are supportive. If the alo prefers you not be there, then make a list of questions you wan answers to and have your child bring those up in the meeting.