Stanley Barnes, eight, was diagnosed with the condition Sanfilippo, likened to Alzheimer’s, at just 16 months.
The youngster, who has a life expectancy of between 10 and 20, cannot now communicate with his parents Mari,40, and Ross, 44, remember everyday words like apple, or recognise his mother at the school gates.
Mari, of Falmouth, Cornwall, who wants to raise awareness of the illness to help others, says brave Stanley is now “like an eightmonth-old baby”.
She said: “He’s quite dramatically gone downhill this year. It feels like you’re losing part of him each day.
“Over the weekend, he had a burger and managed to say the word. Honestly, I nearly cried. We haven’t had that recognition or anything for quite some time.”