Water In Baby's Brain

hi there
my sister has a twin they are 1 year old the baby girl has water on brain. they put shunt in her brain.
she is doing very poorly. she doesnt have any physical problem though but her head is enormously huge. recently she had infection and she has been in the hospital for the last 3 weeks my sister is so depressed. could you please give me some advice? the other baby(baby boy) is doing great he doesnt have that issue and my sister always compare them together and thats why she is upset. because he can walk sit do normal things but the little girl can not eve turn her head because it is heavy