
Hope your daughter isn't too upset, it's a bit of a shock if you're not expecting it.
If it's your Aussie Terrier, maybe he's just had enough of the "same old, same old" ?? I know with my terriers, even tho they can be quite soft and even 'houndy' at times (compared to most other terriers

) going to a handling class or ring-craft class weekly or monthly would bore them. I've also seen others in the breed who have been over 'ring-classed' or shown, have also had enough and refused to co-operate. I'm sure it's not just our breed tho, I've heard of other dogs who one day just 'say' enough!
Can't help thinking the person in charge/teacher should have been able to read the dog's mood better tho
Maybe your daughter could find/borrow another dog or even dogs to take to handling classes? That way she could carry on and your boy could have a rest
Hope it hasn't put her off, these things just happen sometimes. It may even be a 'blessing in disguise' if she gets the chance to work with a number of different dogs and gain more experience

Regards
Dill
Life is what happens while you're making other plans...