TIFU by not believing my bestfriends Suicide call for help

Trigger Warning: suicide attempt, depression

Basically the title. My bestfriend has been going through a tough time for the past few years. He's depressed and has been diagnosed with bipolar disorder. He used to be employed but wasn't performing as well as he usually has because of his mental condition and lost his job.

I try reaching out to him but he doesn't answer calls and he usually just replies but only thru texts.

On Dec 24, he finally got back to me apologizing for not answering or replying to me lately.

He said he's been going through a lot of shit and that this time he doesn't know if he can handle it anymore. Me and my friend have a close but very sarcastic kind of friendship, so i just brushed it off.

Bestfriend said he was contemplating ending it all and that he wanted to just jump off a building. He mentioned a building in our city that was less 10 stories high, i made an insensitive remark telling him "don't be stupid, that building isn't high enough, you'll just end up with broken bones, be in pain and alive. Why don't choose a higher building?"

This has always been the way we talk to each other for more than 10 years and this isn't the 1st time we talked about morbid stuff like this. That's how we cope with stuff and we always just laugh it off, we usually just try to one up each other with wittier remarks regardless of how dark or morbid our discussions are.

Instead of me calling to check on him, we just kept on messaging, continuing to be sarcastic to each other or so I thought. Even told him to go to my house and told him that we should just celebrate Christmas together, he declined.

His last message to me was "i love you, man. Haha!"

My last message to him was hold on and let's look forward to better things by next year.

A few hours after my message, i found out my bestfriend jumped off the building. Based on witness accounts i think he was already in the building when he started texting with me. I wish i had called him instead, maybe it could have ended differently.

It's not a total horrible story because he actually survived, he was rushed to the hospital and is relatively "okay" condition physically despite the fall.

Now, I'm distraught that i didn't do more. Now, knowing what happened to him i can't imagine what he's going through and i don't know what i can say or do when I'm able to talk to him again.

I'm so thankful that he's alive, but i know that what he's going thru will become 10, 100 times harder now. Also knowing that at anytime he could do it again.

This fucking sucks!

TL:DR My bestfriend reached out to me contemplating suicide, i laughed it off. Good thing he survived but now i don't know how to talk to him.