hi, thanks for writing. i have understood your concerns.
depression is very common in the society.your sister is suffering from the depression but you have not mentioned the duration of it. if the person has sadness and some difficulty in concentrating then it is mild to moderate depression.
In
severe depression person develops hopelessness, helplessness and worthlessness. after starting thinking like this person develops suicidal ideas and try to end the life. this is very severe and should not be taken lightly. do not think that person wont do anything, most of the people before commiting
suicide atleast tell to one person that they want to die.
So consider it as a severe depression and take her to the
psychiatrist. there drugs available that can treat depression.after taking drugs when she has improved she can also go for
psychotherapy.
in my opinion she should be taken to a psychiatrist ASAP and get admitted to psychiatric nursing home. before that there should be a person to look after her, be cautious that she should not act on her suicidal thoughts.
i think this will be helpful to you, best of luck..