Christmas Special and famous editorial

[Alien1992]

hi guys
I hope you'll help me to find the answer. I can't understand the following thing. It is the dialogue between Mr. Foley and Mr. Willoughby:
Mr Foley: 'Excuse me, Dr. Willoughby. You busy?'
Mr. Willoughby: 'George. I mean, Santa.'
Mr Foley: 'I just thought I'd stop by to wish you a Merry Christmas and to give you this for the hospital.''It's not much.'
Mr. Willoughby: 'Well, thank you, George. Thank you very much. Marry Christmas to you too.''Where should I send your receipt?'
Mr. Foley: 'Don't bother. Don't open it until tomorrow'
Mr. Willoughby: 'Did you give out all those presents?'
Mr. Foley: 'Well, all except for that oddball.''Tiffany took it, and then she gave it back.'
Mr. Willoughby: 'Well, all she really wanted was to see you for Christmas.''One of the other kids told her there's no such thing as Santa. Then she asked me if it was true.'
Mr. Foley: 'Well, what did you tell her?'
Mr. Willoughby: 'Well, I showed her this.'
Mr. Foley: "Yes, Virginia, there is a Santa Claus."
Mr. Willoughby: 'The most famous newspaper editorial of all time.'
Mr. Foley: "He exists as certainly as love and generosity and devotion exist. How dreary would be the world if there were no Santa Claus. It would be as dreary as if there were no Virginias. There would be no childlike faith then, no poetry, no romance to make tolerable this existence. The eternal light with which childhood fills the world would be extinguished."
Mr. Foley: 'Tiffany?'
Mr. Willoughby: 'I can't do anything for her.' 'What are you supposed to say to a girl who's not gonna see another Christmas?'
End of the scene.
I don't get how Mr. Foley guessed that Tiffany was terminally ill. By reading an article?
I've read both Francis Pharcellus Church's article and Virginia O'Hanlon's letter. The article was written in terms of idealism. Аuthor declares the primacy of idea in relation to matter and touches upon the issues of being, faith, importance of creativity and fantasy in human's life.
Sorry if I said sth stupid, I'm not a philosopher.
So after reading this article, in which complicated things are explained by simple language, a child should understand the importance of faith in good. And if there is no good at all, it's up to everybody to create it, first in our minds, then in real.
It is a great article, isn't it!
But I still can't understand Mr. Foley's logic.
All right, I thought, maybe Virginia O'Hanlon had a fate similar to Tiffany's? She was ill and died in her childhood? Fortunately, no. Wikipedia states the following: "Douglas died on May 13, 1971, at the age of 81, in a nursing home in Valatie, New York." Douglas was her husband's last name. She was a school teacher, by the way.
To sum it up, i dunno how Mr. Foley guessed about Tiffany, if i were him, i couldn't.
Either I am dumb or I don't get it because I'm not an American.
I humbly ask to share your thoughts about it.

[Calmly Taken Flame]

This is quite a recent post being from 2019 !

Watched the Christmas Special the other day, and always wondered about this scene, as I know nothing about this letter/editorial
and how it might alter the scene, or shed new light on things. But from what I can gather, maybe it helped Tiffany come to terms
with what was happening to her, and made her less afaid of what was coming, no matter what happens.

Maybe it gave her renewed faith, and strength for the time she has ahead, and left in this world.

Or maybe, it`s an article Mr Foley knows REALLY well, and has quoted to other people over the years, the ones who lose faith in
good, and in Christmas being a special time of year, and he would use this editorial, and it would help people believe once again.

And the Dr knew how important it was to Mr Foley, and knew it would help him, as he went through his own battles, and struggled to
see the good that was still in this world, and he used this to open the subject of Tiffany, and how bad things are for her.

But I expect she might have told Mr Foley, which is how he knew, she seemed a confident, and bright girl, and had a great relationship
with him, so she would likely have shared it with him, as some point when they were talking.

And of course, he could have worked it out himself, seen her charts, or overheard Doctors talking about her, and found out that way.

But then he IS Santa isn`t he ?! so maybe one of the Elves told him !

But his story arc becomes even stronger, if you think that it`s Tiffany`s illness, that finally pushes him over the edge. He`s lost his beloved
wife, and then he learns that a little girl who he has a great relationship with, is sick and won`t recover, and he knows he`s going to lose
her as well.

To just hear the news that Tiffany is sick, and can`t be helped, must have been a crushing blow to him, at a time when he is already
questioning things, and how life can be so cruel, and so he made the decision to give everything he had to the hospital, and the home
to the Tanners, and then wanted to be with his wife in the afterlife.

But then ALF comes along, and changes his mind, and so we know that it`s very likely, that Mr Foley remained in the hospital, bringing
laughter and smiles to sick children, and that when Tiffany finally left this world, he was there to hold her hand, and remind her that
it`s not the end, it`s all a new beginning, and we get to see once again, all those that we love, and who we miss so so much.

Cleavon Little, and the girl who played Tiffany were OUSTANDING in this episode, as hard as it can be to watch, this was a PROPER Special !

But I would have LOVED to see an episode in S3/4 where Mr Foley came to the Tanners for Christmas !