One of the things you could do is help her see how valuable she is in the Creator's eyes.
Note what what God gives to help the depressed
Strength. God “refreshes and cheers” you, not by removing all your problems, but by answering your prayers when you pray for the strength to cope. (Philippians 4:13) You can be sure that he’s ready to listen to you, for the Bible says: “Jehovah is near to those that are broken at heart; and those who are crushed in spirit he saves.” (Psalm 34:18) In fact, God can hear your call for help even if you can’t put your feelings into words.—Romans 8:26, 27.