It is said kindly sometimes, and cruelly other times, but underneath it is always the same idea: that the child is choosing this, and that somebody at home has failed to be firm enough.
That idea is wrong, and it costs children years.
A difference in how the brain works
ADHD is a difference in the way attention, motivation and impulse are regulated. It is not a shortage of intelligence, and it is not a shortage of discipline at home.
The part of the brain that plans, starts, holds and switches tasks works differently. It responds strongly to interest, urgency and novelty, and weakly to the things that are simply important. That is why a child can build an elaborate world for four hours and still not manage to put one sock on.
It is not about caring less. It is about a different starting mechanism.
What it looks like from the outside
Forgetting instructions that were given twice. Losing the same water bottle every week. Talking over others without meaning to. Moving, tapping, rocking, standing up. Starting five things and finishing none.
It also looks like a child who is quietly exhausted.
Many children with ADHD, especially girls, do not look restless at all. They daydream, they lose the thread, they nod along and hope nobody asks a question. They are often described as sweet but scattered, and they are missed for years.
The effort nobody sees
A child with ADHD is usually working harder than the children around them, not less hard. Sitting still is work. Following a three step instruction is work. Not answering the interesting thought in your head is work.
By the time they get to the actual task, a large part of their energy has already been spent on managing themselves.
That is why so many of them fall apart at four o'clock.
Why blame makes it worse
When a child hears that they are lazy, careless or difficult often enough, they stop hearing it as feedback and start hearing it as identity.
Then something quiet happens. They stop trying in front of people, because trying and failing in public hurts more than not trying at all. What adults read as a lack of motivation is very often protection from shame.
What helps instead
Shorter steps. One instruction at a time, said once, then written or shown.
Make time visible with a clock or a timer, since time blindness is part of the picture. Allow movement rather than punishing it. Put the things that get lost in one fixed place. Start hard tasks together for the first two minutes, because starting is the expensive part, not continuing.
And notice effort out loud, not only results.
One sentence to swap
Instead of: if you wanted to, you could.
Try: what would help you succeed at this?
The first sentence asks the child to prove something. The second one puts you on the same side of the problem. Children with ADHD do not need to be convinced to care. They need the task made possible, and an adult who believes they were trying all along.