A couple from Manchester, who want doctors to keep treating their brain-damaged baby son, are waiting to hear if they have won a Court of Appeal fight.
Three appeal judges have analysed evidence relating to four-month-old Midrar Ali at a hearing in London.
Sir Andrew McFarlane, Lord Justice Patten and Lady Justice King heard arguments from lawyers representing Midrar's parents, Karwan Ali and Shokhan Namiq, and doctors.
They said they would deliver a ruling on Friday.
Mrs Justice Lieven, who analysed evidence at a trial in the Family Division of the High Court in Manchester, recently ruled that life-support treatment could lawfully end.
Midrar's father has said that his little boy is putting on weight.
Karwan Ali said doctors cannot be 100% sure that his four-month-old son Midrar Ali is dead.
Midrar's parents say treatment should continue and want appeal judges to overturn Mrs Justice Lieven's ruling.
They say Midrar is still growing and say doctors cannot be sure that he will not improve.
Mrs Justice Lieven heard that Midrar had been starved of oxygen due to complications at birth and had been placed on a ventilator.
A barrister representing Midrar's parents told appeal judges that more tests should be carried out.
"The child is surviving week by week," said Lord Brennan QC. "Growing."
Lord Brennan added: "The child is still alive in the sense that he has not collapsed into some sort of disunity."
He suggested that, in some other countries, different tests would have been carried out and Midrar might not have been declared dead.
Bosses at St Mary's Hospital in Manchester asked the judge to rule that ventilation could lawfully be withdrawn so Midrar could be allowed a "kind and dignified death".
The court earlier heard that staff at St Mary's had been "psychologically affected" as a result of having to care for Midrar.
Lawyers representing the hospital's governing trust, the Manchester University NHS Foundation Trust, said three tests had confirmed brain stem death.