Something similar happened to me once… I was visiting LA with my girlfriend, pretty soon out of University and still living in NC. I had an informational interview at RKS and we didn’t know LA so I didn’t want to just drop her off on a corner somewhere for the interview, soo… she came in with me. Their meeting rooms were full, so had the interview in the lobby table and since she was obviously with me, they invited her over to join us! I played it cool, but was so worried about the same thing - was it professional, did it make me look bad, what did I do!? It all went smoothly, they actually thought it was cool she joined. Believe it or not, one of them later said they thought I did it on purpose to get a second opinion on how things went!
Anyway, my point is that it probably didn’t appear unprofessional at all - since we all have Moms, all sometimes need a someone for a second opinion, and the reality is that work lives can overlap with personal lives in the professional world and how you handle it can actually make you look better.