I am looking for a story which I read a long time back but cannot recall the name. The plot line was:
In a futuristic world, there are dream parlors which provide sleep with dream services. The protagonist is a frequenter of them.
One day, it was found that he is unable to wake up after slipping into a dream. All efforts to wake him up fail, and he keeps on dreaming and sleeping but is medically fit otherwise.
He became a medical case study and was kept alive for centuries. By studying him a lot was learnt about hibernation and the code to interstellar travel in hibernation was cracked through that knowledge.
Eventually after a few centuries the government asked his custodians for justification for spending billions per century to keep him alive.
His custodians revealed that:
he is the last person alive who is capable of dreaming. The entire human race has lost the capability to dream. So he should be kept alive as long as possible as a rare treasure to humanity.