What can I do? They feel like no one cares about them anymore, and they feel like if they were gone no one would care. Please help. what can i do

Tell them you care, maybe?

Talk to their parents/guardian, and try to get them to consult a medical professional. Been there myself, your friend will need familial and platonic support in the months to come, but it's extremely important that they get professional help.

>>3 I can't, they know already about her previous self harm. They insist she is "smart enough" not to need meds and therapy isn't helping her at all.

Tell them they matter to you and that you care about them constantly (everytime you talk), remind them that you'll be sad if they were to die, spend time with them and have dumb fun, and make memories. I don't know if these help but I do hope the best with you and your friend.

>>4 Wow, that's an awful thing for her parents to be doing. Can you perhaps try convicing her to contact another therapist? Or get her to speak with her doctor so she can get help in other ways? And if her parents aren't willing to help her, does she have other family members (grandparents, aunts/uncles, etc) or parental figures/adults in her life that can help her out?

Also, and I don't mean to sound rude Thorns, but "reminding" a suicidal person that "you'll be sad if they were to die" has the potential to backfire. OP’s friend might for example blame herself for making op sad, she can regret opening up about her suicidalness in the first place, or she might think that the op doesn’t care about her as a person, but only cares for her as a friend. And if you "constantly" say to your friend how much she matters to you, she might very well end up thinking that you’re pitying her and doesn’t really mean it. Basically what I'm getting at is that you have no real way of knowing how a suicidal and likely depressed person is going to react to the things you say. It’s common for suicidal/depressed people to overthink and see things that aren’t really there. I might be projecting, but I know I did that a lot when I was depressed. I lied to people I loved all the time, and were pissed or sad or upset at them in private. That doesn’t mean, >>1, that you shouldn’t tell her that you care for her, just be careful with what you say.

This is a terrible burden on you anon, one that you shouldn't have to bear, and please remember that you also need to take care of yourself. And again, what’s most important is that your friend gets proper professional help.

(And I’m just saying, I am not a medical professional in any sense of the word. This is all based on my own experiences with depression/suicidalness, and from having close friends who’ve also been depressed and suicidal. Ultimately, these things are going to differ a lot from person to person.)

the friend has to feel that they matter. that they are loved. that somebody actually gives a fuck about them. be there for them. show that you care.
If their therapist doesn't care show them that they can go to another. make them understand that they have different options but the most important thing to do is to make them feel loved.