my friend tried to commit suicide

My friend suffers with depression like I do and today they tried to starve themselves to death. I couldn't do anything about it but try and help them via text messages.

I feel awful about this but I threatened to call an ambulance to get them hospitalised. They begged me not to because they really didn't want to go. I asked them to promise me to at least drink a glass of water. I hope they actually did. I'll check in on them tomorrow, I can actually go round to their flat.

I feel awful for threatening to call an ambulance, but I didn't know what else to do, I can't let someone I love die. I have experience with hospitalisation and it saved my life. But the last thing I want to do is be controlling over them because that could make them feel worse.

I don't know what I can do.

At least two weeks are needed to starve oneself to death.
No need to freak out with one day of not eating.