If I understand what you're asking, your last sentence could be condensed to this:
"Can a simple conversation enhance a person's mental health?"
The answer appears to be YES. Isn't that why people consult psychoanalysts?
People who are in great pain also often turn to religion, and many of them are rewarded with a lessening of depression. People can find similar release through a variety of activities that might be described as "escapism."
They can also turn to philosophy, which can overlap with religion.
However, your first question, "How can philosophies be used for healing people with mental issues," is more complex.
This subject kind of blurs the lines between philosophy, religion/spirituality, psychology and medical science.
Though my answer is pretty shallow, I felt compelled to answer it largely because I've been asking questions similar to yours.
Imagine being deeply depressed but not knowing why. You assume it might be related to the fact that you spend so much time focusing on gloomy issues. Maybe you're a political activist or environmentalist, for example.
And so you go to bed in a deep depression one night. But when you wake up in the morning, you feel like a different person. You feel uncharacteristically happy.
Recalling how you felt the night before, you force yourself to think about some of the same dark issues you were thinking of earlier. They still induce a feeling of sadness, yet it doesn't weight you down the way it did the night before.
It's a very different feeling. I would describe it as being happy and sad at the same time, as opposed to being just plain depressed.
This would appear to be "chemical thing," where pondering something sad brings you down one day, then doesn't hit you nearly as hard the next.
But I also know from personal experience that rational thought can help one create a mental "road map" that is somehow comforting.
It's an incredibly hard thing to understand or research, partly because the terminology is such a challenge. As I mentioned earlier, this topic also overlaps with philosophy, psychology, etc., which makes it difficult to find a place to discuss it.
Two people have already voted to close your question, and if your question is deleted, it will likely be deleted from a biology or psychology forum as well.
However, I want to eventually explore your question - or something similar - on my new philosophy website. I still have a lot of things to figure out myself, though.