90mL!!! That's loads!!! So the LC is assuming baby gets *nothing* at the breast?

How does your friend feel about all this? Is she wanting some other ideas? I'd suggest giving the ABA a call and/or getting a private LC in to have a chat about what's going on. She really needs one-on-one advice, because there's clearly a lot of stuff going on here.

Feeding more frequently during the day may be a great idea. Four hourly is pretty unusual, but if baby isn't asking more frequently it might be because of the formula. Whereas, if that is removed (and 40mL is quite a lot, really) then baby might simply feed more frequently to make up the difference. UNLESS, baby isn't feeding effectively at the breast. Which is something that needs to be assessed by LC and help given to mum and baby.

Skin to skin and laid back nursing may help with the sucking issue. has baby been assessed for ties? Also, she may need little extra help after traumatic birth, separation from mum and bottles early on. She probably just needs some more time. Laid-back nursing is good for this, also. And, an LC

It's a bit hard to offer useful info at this remove. Suggest your friend seeks more professional help. Just because an LC has said this doesn't mean another LC mightn't also have good suggestions for her.