This sounds like my experience. I had an unscheduled Cesarean, but no labor beforehand. Are they taking the babies early? There is still a trend among OBs to call twins "term" at 37 weeks, and schedule (often) unnecessary Cesareans early. Near-term babies have trouble breastfeeding, twins or singletons, so if they will be early she should be prepared for this. No labor means no hormone stimulation for mom and babies, so sleepy babies are likely. Mom's milk might come in late as well. Good to be prepared, make sure she tracks how often each baby is nursing, teach her what active nursing looks and feels like. No one helped me with this; my babies were 4 days old and more than 10% under birthweight before I learned that although they were spending a lot of time at the breast, they weren't actually moving milk. Teaching her about breast compression to ensure babies are getting plenty of colostrum is a good idea, too.
I'd strongly recommend the book "Mothering Multiples" by Karen Gromada. Lots of good info and ideas for moms of twins, including lots about preemie and near-term babies, dealing with separation, ways to increase supply. Is there a local twins support group? NOMOTC (Natl. Organization of Mothers of Twins Clubs) is a good place to look for a local group. Be warned though that groups vary widely in their style of parenting & she may or may not find support for breastfeeding. But it's so very helpful to have IRL support from someone who knows what she's trying to manage!
Is the hospital at all breastfeeding friendly? Many hospitals now realize how important early skin-to-skin and breastfeeding is, and will keep baby on mom's chest after delivery while the doc is closing the surgical incision. This is more challenging with two babies, but not impossible if she has help. She can be insistent about having support in the OR and keeping the babies skin-to-skin as long as they are breathing well. I was told "one" support person, but when I made it an issue, I ended up having my DH, my doula, and my CNM friend all there. We joked about the "cast of thousands" - OB surgeon, backup surgeon (happened to be my family practice doc who wanted to be there for us), anesthesiologist, nurse to help each doc, nurse for each baby, respiratory therapist for each baby. . . crazy. No one offered me the option of keeping the babies with me, and I didn't know enough to insist, so they were taken to the nursery despite having no issues after birth. It took an hour for the nursing staff to return them to me after I was in recovery. No reason at all why they needed to be separated from me. They also did all the postpartum "stuff" to them (including unnnecessary eye ointment - for Cesarean babies!!), baths, etc, so she might want to put what "routine" procedures she will allow in her birth plan. Since it's a scheduled Cesarean, no reason not to schedule it when an IBCLC will be available to consult within 24 hours of birth, also good to have in her birth plan. Again, she might have to make noise for this to happen (assuming that the hospital HAS an IBCLC on staff. . .).
If the babies have respiratory challenges, they will likely be taken to the nursery for some period of time. If separation seems likely, making sure she starts pumping or hand-expressing colostrum ASAP. She might have to be insistent about this and it might be hard while she's recovering from surgery.
Good luck to her. She's lucky to have your support. She already has taken that major step by hiring a doula, so it's clear she has some ideas about what will help.