We don't know that.
It's been reported (BBC) that the hospital is speaking with Govt lawyers to understand the implications of the request from the UN.
It may well be decided there are no implications at which point there's a decision to be made on how to manage the situation.
To wait for the UN and the family to run out of road or press ahead specifically to stop any future cases using a UN request as a precedent to thwart U.K. law.
I suspect there's a lot going on behind the scenes between the U.K. Govt and the UN.
It's sad to have to talk about money, but the costs of this case must now be astronomical in terms of PICU care, NHS and Govt legal fees, plus the massive amount of admin time etc. All that could be used supporting a child who is alive.
Hollie wants time, but she's not footing the bills here and it's fecking huge to keep a brain dead child in a slow state of bodily decay.