She needs to go to a tertiary hospital. T18 can only be diagnosed via amnio or birth. She can have an amnio anytime up to birth. Until that is done, everything is just supposition. She should also talk to a genetic counsellor, which can be provided at a larger hospital. As HotI said, some T18 babies are born alive.

If the baby does have T18 and someone knew and she wasnt advised earlier, then the hospital and/or doctors have been negligent. If baby does not have T18 and she's being put through this, then they are being negligent.

What she needs is to be referred to a Maternal Fetal Medicine unit at a tertiary hosital asap. If the doctors at her hospital dont do that then she can just show up herself.

ETA - we were posting at the same time. Hoping baby is fine. The staff at that hospital need a swift kick up the rear.