1) Dont get a letter from your Mom even if a physician
2) I presume this is an EC on your application and therefore your Doctor Mom is the contact? I believe in being transparent so there should be AT MOST a passing phrase "worked as scribe/MA in private practice owned by my physician parents" even that I am not sure of
@Catalystik @gyngyn your thoughts please
3) do not mention it in your PS. Do not highlight something that you perceive as weakness in a negative way. All you do with is insure it will be seen in as a weakness in a negative way.
3