Thankyou for the responses.

My parents, although in their early 80's, by no means could be considered to need mobility assistance. I was more concerned with just being with them through security and finding their gate. I know this is straight forward, but also know they are worried about it.
I am interested in any experience about obtaining a gate pass. I would inquire directly with Qantas, if I could somehow reach the LAX counter by phone. Recent experience with the SA based "help" center has not led me to believe they will even know what I am talking about.