I know Alder Hey aren't making any further comments, but I do wish that someone medical would explain to the public that 'breathing on his own' isn't enough to sustain life. My mother was on the Liverpool Care Pathway, aged 94, after 5 years of dementia. She was breathing on her own till her last breath, but all the time her oxygen levels were going down. This meant that her vital organs were failing until her heart eventually stopped. It's part of the dying process. In her case it took nearly 9 days. Giving her food or water would have made her death more painful. Her lungs would have been water-logged and her stomach couldn't digest food.
I saw a programme in which doctors tried to raise the sats of a child when they were dangerously low through a chest infection. I think 60% was the danger limit when she would go into cardiac arrest. She had a lot of medical problems, but she had a good life, and everyone, parents and doctors wanted her to go on living it. They did manage to save her.
Alfie can't survive on oxygen through a mask. He needs to be intubated and the air forced into his lungs to bring his levels up. But that would be taking him back to his previous state, just waiting for disintegration of his brain to reach his brain stem. It's a horrible process to be intubated and have unpleasant procedures to clear secretions from your lungs. This is Alfie's 'life'. Patients without brain damage are usually sedated while intubated. Or have a tracheostomy, which is the only 'treatment' the Italians have offered, I think. And why would you put him through the stress of surgery at this point? By all accounts, even just being moved in his bed triggers a seizure.
Let him die peacefully, with dignity.
So sorry about your own experience, Op. 
At least my mother was at the end of a long life, well lived, but it was so hard to watch.