@21themoon
"Second, don't act like you are the one who need help, in my case when I selfharmed my parents cried and felt scared."
As someone with chronic depression who has dealt w suicidality, as well as a person who has supported many others through mental illness, I try to see it from both sides.
Those who are struggling need support *and* those supporting them need it, too. But, yes, to your point, it's unrealistic for friends and family to expect it to come from their suffering loved one.
What I've seen happen a lot is that parents and loved ones don't seek adequate support from outside, think they need to handle it all on their own, and burn out or get overwhelmed or angry.
When that happens in the presence of the person with mental illness, it can feel like they're being asked to carry the other person's feelings in addition to their own. Basically, it can be felt as a boundary crossing that leads to angry reactions in the process of reasserting the boundary.
I think it's important to remember mental illness is hard on everyone involved. And also that no family unit can deal with it effectively unless they have outside support.