Here is my take

:
"I thank for you for your
kind letter,
& I offer you my"
"....&
he was such a very
good boy
& so little
trouble"
"I hope Mr Snow got all
Certificates in good time.
With my kind wishes to
you both & again my
best thanks for your letter
Yours, Frances
Murphy Matron
The first time "thanks was written in the opening para, it looks like there are all sorts of extra letters in it! Which is which is why I think it is "thanks" again in the closing para. It makes sense also because in the last para - Matron is closing with a re-iteration of why she wrote in the first place (to thank Mrs Snow for her letter) I would say an educated manner of letter structure ie: "again thanks....." ?
I also think it's not "Sincerely" - though it looks like it might be. I don't know if "Sincerely" would be the appropriate word in such a deeply personal letter? besides which the last letter doesn't look like a "y" elsewhere. I think it's Matron's first name -possibly "Frances" and not crossing her "F". Also, think her surname has no 'e" in it, so just Murphy.
I also think it "holy innocences" ( that's a common religious prayer - & the liturgical "Feast of the Holy Innocents" is 28 December); and I agree with "must all be resigned", and "fretting" as others have found.
Just curious - how old was great great uncle when he died of pneumonia in 1924?
Cheers
AMBLY