I'm back for my update 
I was out of it from my c section and because my 2 were under 6lb, they advised topping up with formula from the word go, as it's not good for them to lose any weight whilst waiting for the mothers milk to come in. I just did what I was told but really wanted to breast feed.
Midwives advised me to put the babies to the breast before each feed but they would do 2/3 suck and fall asleep. They were pretty much asleep for the first 3/4 weeks
I miss those days.....
Anyway, I was expressing milk using the hospital pump, 3 hourly even at night. I found it quite easy and produced a lot of milk, but I know it can be difficult. I had the girls next to me as I was lucky enough to be in a private ward due to my company health insurance.
First 2 weeks I would put baby to the breast, then give them expressed milk and then top up with formula, then express for the nex feed. They would be asleep and it was a nightmare literally squeezing it down their throat. Luckily I had my mum with me and DP for help in the evenings, I did nights on my own.
They slowly started being awake more and suckling on the breast more, when they were 2 and a half weeks old I stopped the top up and only breast fed. Midwife weighed them and they were putting on weight and thriving.
Since then I've found it a doddle and as I said before we're coming up to 6 months. I still prefer feeding seperately but sometimes you do have to do both, I was always fine tandem feeding on my own. I'd put the babies on the middle of the bed, surround myself with pillows and then latch both on. Later I bought the EZ2 nurse cushion. I'm usually on my own too, DP works long hours and you just get on with it. Hard work yes, but fun and a joy all the same 
Once your friend is feeling better, tell her to come and find some twin mums on the multiples boards, very friendly and lots of help 
Good luck 