He'd still be under the care of the hospital trust I expect, so the order would still apply.
When my child was in hospital, we were able to leave to take her to the cafe, and on the occasions she was well enough, to the Ronald McDonald house. If the opportunity had arisen, we'd have been able to take her 'out' or even on home leave for the weekend.
It was clear though that she was still the hospital's patient, and if she didn't return at the allotted time, wed be called, and if they couldnt get hold of us, the police would be called.
There are many reasons why transfer to a hospice may not be practical here, but jurisdiction of the order probably isn't one of them.