Sometimes I write extremely thought out responses to people in crisis only to delete them.
That doesn't seem helpful. Why would you delete the responses?
I don't know if my responses are any good so I'm scared to send them.
You are doing the right thing by wanting to help, so why are you stopping yourself by deleting the messages? They will for sure need it and love the help they are getting, but since you aren't sending it they think no one cares. They might eventually hurt themselves because you are too scared to send a good message.
What if they don't help, though?
I'm sure if you're writing heartfelt replies to people who are going through a hard time that they'll appreciate it no matter what. Sometimes people just need to know that someone is listening to them and is there to offer support.