Wow, that sounds so stressful!
Would you consider trying 1 ounce once every hour during the day?
Not letting him sleep longer than 2 hours at night is a good idea at this point.
The only reason I can imagine for talking about formula is if the doctor is considering human milk fortifier to get more calories and nutrients per ounce into him. But HMF could be added to breast milk.
I'm sorry you're going through this!