No, the female assistant makes no mention of her being Dawn's mother, which stands out against the male making mention of it whenever you speak to him.
I don't know if anyone has mentioned it yet, but in Generation 6 Serena's parents are Ace Trainers who she's trying to impress, which is something I can really relate. Also in Generation 5 (the home of awful parents.) Bianca's dad outright refuses to let her go on a journey. (man Pokémon has awful parents.. cept maybe Norman)
Well, the thread was specifically about Dawn's parents, but yeah, it's generally accepted that parents are absent/absent-minded in general when it comes to this series. I think that in the manga Brendan gets into a rather heated battle with Norman at the Weather Institute because Norman isn't at home as often as he should.
Don't Know if Anyone Mentioned this yet but dawns father and mother is revealed in the manga , they both showed up in VERY CLEARLY in the last Sinnoh Pokémon adventures manga, and yes i know this is about the game not the manga,but the manga have some points that are related to the game.
I haven't even played Diamond/Pearl/Platinum and yet I knew about this. I got the Pokédex/game guide for Platinum and it specifically points this out.
To be fair, there's always been a loose - at best - connection between the games and manga, but that's nice to know regardless. I know Dawn has a mother in the anime (used to be a Coordinator, IIRC), but in the game there's just the dad. I read a fanfic that explored that. That's an interesting detail; I haven't seen the players guide for DPPt, so it's nice that they pointed out that detail.
I knew that Dawn had a mom and dad from the manga though I don't think I found that dialogue in game. According to the manga, Dawn's mother is a researcher that works for Rowan just like her father. I always take this with a grain of salt since the manga isn't canon, but I still like to believe that this is Dawns canon family.