She has only told one friend (yesterday) and me (today) about this, other than her GP who arranged counselling at the time.
She has a very difficult relationship with FIL, who has mental health issues following a breakdown nearly 20 years ago. They have an unhappy mutually codependent relationship. We (my husband and I) have tried to support them as much as we can, but things are gradually getting worse and they are spiralling into deep unhappiness with their current situation, though neither seems to have the energy to change things (themselves, their behaviour, or their situation). They have had Relate counselling in the past but I don't think it really helped them, and neither have much faith in counselling as a tool to help them individually or as a couple.
MIL told me today that she tried, but failed, to kill herself a few months ago when FIL had left for a few weeks after a particularly bad episode. After she told me she then asked me not to tell my husband (her son) and I assume she would expect this to extend to my SIL (her daughter) with whom I and my husband are close.
I feel awkward about this because I don't keep secrets from my husband, but at the same time he would understand my need not to break the confidence.
Her revelation has taken the wind out of my sails. I knew things were bad but I would never have expected her to attempt suicide. She seems better now, but things are still bad and getting worse for her at home, so she could end up feeling suicidal again.
Our conversation was difficult because we were in a public restaurant and my toddler as with us. I want to do what I can to support her (and FIL) to improve things if possible.
What do I do now?