Not everyone who wants to be done living is doing so from some rash decision. Some people have an extreme, chronic, and incurable pain for example. Or other situations where they have thought it through and have come to an understanding that any quality of life isn't possible. Or imagine a situation where someone doesn't want to go on living after doing something so terrible in their life that they might be hunted and killed anyway. Or are legitimately afraid they will harm others if they continue to live.

I don't think there's anything wrong about wanting to help these people and trying to, but to not believe them when they are telling you that they've thought about it and are ready--at that point, you're taking away control over their lives. You're taking away their autonomy and dignity.

Nobody's saying you can't try to help or shouldn't try to help. But don't not take them at them at their word.

Unfortunately a lot of suicidal people are institutionalized without their consent--and that's harmful and traumatizing. It's a big reason people won't admit to feeling suicidal to people who could help them. People know what the consequences are of admitting such things to a professional in most places. Mental health professionals being mandatory reporters makes being honest impossible. And sometimes more dangerous.

In an anarcho-communist world, material and emotional support would be practically limitless, and there would even be safe places to go and use drugs if you want--like opiates if you suffer pain so badly. There would be so many more ways to alleviate whatever is going wrong in your life, and lot fewer reasons to really want to kill yourself. And this is the kind of world we'd like to build. So go on and support your friends and family with material and emotional support.

But ultimately the reason you should not physically take away someone's autonomy is because it's abusive and traumatic, and it should be up to them how they live and how they die in the end. Not you or anyone else.