Hello,
Tracheostomy is done in such cases to--
1. To help lungs to improve faster as regular suction can be done ,lungs will have to exert less pressure to inhale or exhale
2.to prevent complications of endotracheal tube which if kept for long like 7-10 days --- decrease
oral hygiene ,pressure complications by big tube, lungs have to put more power, patient can not keep it for long and can not be sent home with such tube but with tracheostomy tube patient or relatives can be taught and can be sent home.
Tracheostomy tube can be kept for long duration like months.
So tracheostomy will be helpful.
BUT weaning from tracheostomy (ie when the lungs improve ,to close the tracheostomy tube )is also very difficult in case when patient has neurologic problems as lungs get used to exert less power .
So it is like you have to discuss with your doctor that how much important is putting a tracheostomy tube.
I can not comment as i have no idea about the condition of your sister.
If in doubt do reply.