Didn't walk away totally, but did find a safe distance from which to maintain contact. They did get a bit better and found a more stable way of life and way of thinking, but not quickly enough. By this I mean they didn't commit suicide, but due to ongoing mental health issues they were too scared to seek timely and proper help for another condition (cancer) which did take their life. They did seek help, but a bit too late.
I think if I had done what they wanted, stayed where I was, never made any changes, they wouldn't have found the better level that enabled them to seek help for cancer at all.
However, if I had been in a position to gravitate back quicker when they did start regaining some mental stability and support/re-inforce them in that, I think they might have been in a position to go for help with the cancer 6 months to a year earlier and that might have saved their life.
Also, just having someone close who would have gone on appointments etc with them would have made things easier. I just wasn't in a practical position to do that plus I was scared (probably too scared) of getting burned again.
But hindsight is a wonderful thing. Everyone else who knew the situation properly thinks I had no choice really, and that I made the right choices. I think if I had agonised and doubted myself over certain things less (both the distancing and then the gravitating back), that there might have been time to stitch it back together more fully. i do recognise that their actions were some of the reason I took so long to decide what to do, but I also recognise that their actions were grounded in fear and anxiety and my heart breaks that they ever had an inner life like that.
So my stance would be, find a safe distance, and hover there. Leave capacity to gradually flow back into their life if it's appropriate. Don't get totally caught up in other things and people that will make it difficult to disentangle yourself. If they make positive moves, support them once you see they are serious and gradually gravitate back.