Hello and thanks for posting, 

I am sorry to learn about your partner's sister and can understand this is a stressful time for everyone. 

I'm afraid I can't tell you what is likely to happen to her, the type of brain tumour and it's location would most probably have some bearing on this, but it does sound like the medical/nursing staff looking after your partner's sister aren't expecting her to survive or come around from this coma. So it could well be just a matter of time. The best source of information about this will be the doctors and nurses involved in your partner's sister's care so do try and talk to them when you have the opportunity and encourage your partner to be guided by what they say. 

Most people in situations like this feel helpless and seeing someone this unwell is very upsetting. With your partner, I think all you can do is try to be as supportive as you can be and listen. You don't have to have any 'answers' , just  'being there' can mean a lot. 

If you want to talk about anything please feel free to call us. We are here weekdays (not BHs)  from 9-5, and our Freephone number is 0808 800 4040. 

Wishing you the best,

Julia