After I'd stopped laughing I pointed out that he isn't a cocker spaniel (which her bonkers dog is) and being calm is not the same as lacking in energy. Plus I chose this breed specifically because they are chilled out and patient with kids. 
Mum's dog is lovely but also the exact type of dog that I wouldn't choose for myself. She (she, the dog not she, my Mum) doesn't respect personal space, every time you sit down she tries to sit on you. She never stops wriggling and moving, when we have lunch she paces around the outside of the table and stands up on her hind legs trying to see if there's anything nice for her. She's a bit of a nervous wee-er so you have to say hello to her outside or wipe up inside. She needs attention all the time, which suits Mum because she lives on her own. But just because that's the right dog for her, Mum has somehow extrapolated that there is something wrong with dogs who don't behave in exactly the same way. 