The law won’t let them.
On that note every day I read about more and more medical hope for patients with dementia. If I were these parents I would have had both kids at these clinics for medical testing and what ever was coming out. I’d demand they try out anything/everything even if it was experimental. Something might work you never know. At least try. Abortion is not the answer.
In fairness, you don’t demand anything of the NHS. You get what they decide and shut up.
Not that this is a defense of these people who will one day answer for killing their child. I pity them.
They could move to Canada...