Your friend needs to see her physician for her own health problems, both her mental distress and her weight issues. She also needs to see an attorney re the house situation. The siblings cannot just sell Dad's house unless there is some legal documents giving someone the power of attornery for medical and for legal transactions.
It always breaks my heart when families fight over the money and the family member is still alive. Greed seems to come out at times like this.
The best you can do is remain a good friend and encourage your friend to get help for herself.
A job would be a good thing. Perhaps she could start by volunteering just to get used to being back out in the community.
Take care and your friend is very lucky to have you. ((((((HUGS))))))