Yes prayer is needed, but there is more to it than that, I served on a Crisis Telephone Hotline and this is what they taught us.
First and foremost, if we are hearing about the person that is suicidal that means they are reaching out for attention, someone that will listen to them, someone that will emphasize with them, ......because truly suicidal people don't talk about it, they do it, ...in private without anyone around to stop them.
So we assess the situation by talking to them, listening and asking questions, that way we now where they are in the planning of their suicide.
A. Do they have a plan or method to accomplish the suicide?
B. Have they been or are they just beginning to give away personal items of sentimental value, ...that will help us to know how serious is the threat.
C. From listening to them is there any "hook" we can use to cause them to want to live, i.e., family, friends, pets, dreams, unaccomplished desires, we learn what the "hook" could be from listening to them.
D. After finding the "hook" we talk them in to how to implement it in their lives, gives them a goal to strive for and takes their mind off of suicide.
E. Learn what are their spiritual resources, church, pastor, spiritual friend that knows the Word, family, siblings, anyone they trust that they can talk to and possibly stay with for a while until they are more stable.
All of the time we are listening to them we ask questions only when we don't understand what they are saying, through good listening skills we can learn a lot about their lives because they want to talk and we are listening.
Here is the key to ALL mental problems that we need to lead the people to see,
A Psalm of David. The LORD is my shepherd; I shall not want. He maketh me to lie down in green pastures: he leadeth me beside the still waters. He restoreth my soul: Psa 23:1-3
Do you see what David said about his mental problems,
He restoreth my soul:
Jesus is the great Physican and He is the ONLY one that can heal our souls, you say you know her from church, ...is Jesus her Shepherd?
If so she can and will be healed by Him, if not then you might be the one that the Lord will use to lead her to Jesus.
Praying and blessings.