The family of teenager Jack Bostock, who died last week in Knowle West, have paid tribute to their "happy-go-lucky" brother and son.

They told the Evening Post that 16-year-old Jack, of Brislington, had died after a blood clot on his lung caused him to have a fit.

More than 700 messages of condolence have been left on his Facebook page by friends, along messages and flowers outside the gates of The Park centre where he died on November 11. There is also a graffiti tribute in the nearby Hartcliffe underpass.

His parents, Andrew and Jo, said they were overwhelmed by the show of support and that the family are still reeling with shock.

Jack leaves behind three brothers – Tom, 19, Sam, 17 and Ethan, four, – and a sister Rosie, 12.

Jo, 42, who works in pensions, said: "The kids are going through phases, we are all upset and shocked. We told his four-year-old brother Ethan what has happened, we said he has gone up to the sky. Then the next morning we caught him looking up at the sky and talking to him, saying, 'morning Jack'. We just can't believe he has gone."

Andrew, 42, who has recently sold a convenience shop he owned in Southville, said they had cleared Jack's things from the room he shared with his brother to help him, and that he himself had cried for days.

He explained that Jack fell and hurt his ankle a few months ago, and had a blood clot in his leg – but they do not know if the two clots are linked.

Jack was doing a bricklaying course at The Park, where he had been referred a couple of years earlier. The unit helps youngsters who have problems in mainstream schools, and his parents say he was sent there because he would mess around too much in lessons.

On the day that he died, Jack left The Park over his lunch break with some friends, but as they returned to the school gates he started fitting and hit his face on a wall – but then came round and was chatting to his friends and staff, who called an ambulance. But he soon went into another fit and did not regain consciousness again.

Andrew said: "It was so sudden. They are waiting for more information from a toxicology report, but the post-mortem showed that he died from a pulmonary embolism. There was nothing anyone could have done – that is what we keep telling the boys that were with him."

"Jack was a joker, a real wind-up merchant," said Jo. "The best thing about him was his sense of humour. He always made up his own jokes – but they were never funny. He was a good kid. 

"He would moan if you asked him to help you, but he would always do it. He was great with his brothers and sister, and he loved going round to his big brother's to play computer games on the XBox. 

"Just days before he died he had queued at midnight to get his hands on the latest Call of Duty game – he loved it."

For Jack's funeral, which is to be held on Monday at South Bristol Crematorium, his coffin has been decorated with images from the game.

"He would have absolutely loved it," said his mum. She said her son loved going fishing with his older brother and uncle, and socialising with his friends, especially his best friend Ollie – the two were always together.

"And he was a big, big eater," she added. "We used to call him a gannet – his loves were his XBox, mates and food.

"We just want to say a huge thank you to everyone who has left comments on the internet and where he died, everyone has been so good.

"I still expect to see him walk in. I am just so glad he was so full of life and happy when he was alive. We will never forget him."