Is she seeing a doctor?
An anti-depressant can help her through a difficult time because depression is a lack of chemicals in the brain.
Because of this, things pile up and get bigger than we can contain.
If she could talk with a professional, it might help.

Dear Heavenly Father:

I come to you on behalf of this precious soul that is lost and bound in the darkness of depression. Please send your love into this situation and release this precious child of yours from the affliction of depression and set her free. Grant her favor and mercy and send those into her life that will aid in this process. Father God, if this precious soul does not know you, please give her eyes to see you in the midst of these circumstances and save her from despair and if she already know you personally, may you give her a fresh revelation of your love for her and revived your Holy Spirit within her. Please hear this prayer and touch others to pray for her from the heart. You are a God that is able to do exceedingly above and beyond whatever we may think or imagine. Your holy name is Jehovah Jirah, for you alone is the great provider and I petitioned you on behalf of this child of yours that according to your great name you will provide a solution to this situation. Your name alone is Jehovah Nissa, for you are greater than the giants in our life, please help this precious soul realize that the Goliaths in her life that makes her feel overwhelmed is nothing before your great throne and just a holy word uttered from heaven, in a twinkle of an eye can change every circumstance and cause all things to work together for good for those who call upon your name. Bless this child of yours and bring her unto victory and put a testimony in her heart and mouth of your faithfulness and very timely help in the day of trouble. Father I know you hear this prayer and will answer. Please do this for your own namesake, In Jesus Precious Name. AMEN!

*I will continue to pray for your sister and you as well. God bless you.