The original post left me incandescent with rage, although I'm glad to see the poster is willing to learn more about ADHD and to rethink some prejudices.
My ADHD was diagnosed in adulthood. At primary school, I was a ditsy, dreamy teacher's pet, who devoured every book in the school library, researched each topic until I understood it backwards and was a talented writer. At secondary school I was always among the top few pupils in the top set of my selective school, winning prizes and taking part in lots of extra-curricar activities. I got detentions for my lateness, forgotten books/PE kit etc, late homeworks, but the teachers didn't know about inattentive ADHD and thought I was some kind of absent-minded professor in training.
By 16, I was suicidal from the pressure of succeeding when just starting a piece of coursework, or turning up on time took so much effort.
I don't know what you think ADHD looks like, but we aren't all naughty kids who get into fights. My impulsivity mostly takes the form of finding it unbearable to sit there when someone asks a question or looks for a volunteer, so I contributed loads in class and was on a gazillion teams and committees which I struggled to find the time for.
And having poor boundaries at home is actually pretty consistent with ADHD - there is a strong genetic component, so it's quite likely that your pupil has a parent who struggles with organisation and impulse control, possibly with substance abuse or debt issues and possibly with a history of criminal behaviour. That doesn't mean that the child doesn't have ADHD, but can actually be an indication that they do.