I have a child with hydrocephalus. 10 years old now and, although there are a few issues, he's happy, walking, talking and very sociable. Other than a slightly larger head, which is less obvious as the years go by, you'd never know. He had a shunt put in as a baby, and his development was delayed- but he's caught up now.
I also know lots of other children with hydrocephalus, they're all pretty amazing.
I suspect your consultant will want to deliver your babies earlier to give your little girl the best chance for her brain to heal after birth. Hydrocephalus is treated quite easily but they cannot treat it until she's born. You should anticipate staying in hospital with her for a few weeks while they drain the fluid, even more so if she's born early.
At 28 weeks, I don't think I could consider termination, especially for a condition that my son has lived with for a decade. That's my opinion as a mother of a thriving hydrocephalus child. I am not a neurosurgeon, I don't know your case. You may do your research and think differently, that's totally up to you, I thought I'd share my story.
It's not easy, but it's not the end. X