It should depend on what is best for the baby.
All other considerations should come after that.
Even the halal/ haram consideration.
Life is the most precious the thing and Islam recognises this. We are allowed to eat pork as a last resort. I'm sure many medicines contain alcohol.
I have personal experience of this.
My daughter was born at 25 weeks. There wasn't a baby formula suitable for her at that stage of prematurity, there probably still isn't. My wife was too ill to produce her own milk. My daughter was fed on the milk of an unknown lady, to whom I am eternally grateful, until my wife was well enough.
My daughter survived. She is now a highly educated, productive, motivated asset to society.
Absolutely there should be a milk bank.
Sometimes we get bogged down in whats, ifs and maybes and forget to look at the bigger picture.
God has given us a religion but he has given us an intellect and the faculty of reason as well.