With his happy smile and big blue eyes, it is easy to see why Khyal Heading is the apple of his mother's eye.

Nikki Heading has more reasons than most to keep a close eye on Khyal.

The youngster has severe mental and physical disabilities which means he cannot walk or talk and needs to be fed through a tube.

He is going blind in one eye, has severe lung and chest problems and has to have oxygen every night to help him breathe.

There have been several times in the past two years when Nikki thought she was never going to see her son's smile again as he fought for his life in hospital.

Nikki, 20, and her fiance Terry Pearce, who is in the process of adopting Khyal, have lost count of the number of times they have rushed the youngster to hospital for emergency treatment.

At least four times they have braced themselves for the worst as the child struggled to survive.

But Khyal is a battler. He cannot play with toys like other young children so has to rely on extra stimuli.

One of his favourites is a sensory room at the Chestnut Tree House children's hospice in West Sussex, where he sometimes goes for a brief visit so his parents can have a break.

The room is filled with bright lights and soft music and is one of the places where Khyal is most animated.

Nikki and Terry, who are to marry later this year, are planning to move out of their home in Littlehampton to a larger one with room for disabled facilities.

Nikki looks after Khyal full time while Terry, also 20, works as a railway security officer.

Nikki said: "It has been a very difficult couple of years but we are getting there. Doctors are still not exactly sure what is wrong with Khyal and he has a lot more tests and operations ahead of him.

"There have been some very stressful times but he has come through each time. He is obviously meant to be here."

Khyal was born at Worthing Hospital on December 4, 2001 but his heart was not working properly and he had to have a six-hour operation to repair it at three months old.

He suffered numerous chest infections, leading to bronchitis and pneumonia, and spent his first birthday in intensive care.

Tests showed he had some brain damage and in March last year Khyal faced his most critical crisis when he developed chronic pneumonia and lung failure and had to go on a on life support machine.

Nikki said: "Life is going to be one big struggle for Khyal so we need to make the best of it for him."