My mentally unstable bandmate shot himself in the knee, permanently disabling himself. I'm conflicted on how to handle the situation.

TLDR:

After a show, our bassist accidently shot himself in the leg with a 357 sig. The round hit his car door, ricocheted into his femur, and traveled into his kneecap - completely shattering it. He was intoxicated at the time and also on an irresponsibly large amount of his prescribed anxiety meds. He won't be able to walk without crutches or bend his knee for an unknown amount of time. He will never be the same as a result of this injury. The issue now is that he doesn't seem to be realizing the severity of the situation and he thinks that he will continue playing with the band. I don't know how to tell him that it's not going to happen. He is very suicidal and I don't know what to do.

Full story:

To preface this, we have had issues with him in the past. He was struggling with addiction for a while and we were essentially going to kick him out of the band because he was using the band as an excuse to get loaded and party. We take things very seriously and are quickly gaining momentum as a band.

When we confronted him and told him we were kicking him out he broke down and cried, begged for a second chance, swore to get clean - and to his credit he did. During this he also said he had nothing else to live for and would likely kill himself if he didn't have music…

Fast forward to the day of the event, it was evident he was on too many of his prescribed meds, his eyes were drooping and he seemed off. He claimed a lack of sleep but my other bandmate knew something was off. After the show, he was drinking. We loaded our gear up and when he came back to the venue to hang out he had his gun on him, claiming a random woman pushed him and he felt in danger due to there being a lot of drunk people out on the street. (we play in a big, dirty city). I expressed my concerns about it being illegal to have that on him at a bar, and told him not to show anyone that he has it.

Going back to our cars, he claims he was almost jumped by 3 people, he took his gun out and cocked it, putting a round in the chamber. They back off and he goes to his car. We're on the way back to our practice space in two separate cars to unload, and he was by himself, so I cannot verify his side of the story.

His car arrived a while before ours, and the moment we pulled up his gun went off and he fell over out of our sight. We were frozen in the car for a few seconds when he comes crawling out from behind his car screaming for us to call 911. My other bandmate calls the police, and I run to grab a shirt to tie the wound after seeing the extent of the injury. I tied a clean rag and shirt on his leg to stop the bleeding. It was an extremely traumatic situation.

When the police arrived, they told me had I not done that, he would have likely died, and that he was 1cm from hitting his femoral artery... His condition is very bad, he's missing half his kneecap, and tore many tendons and muscles. He's not getting a knee replacement not but he will have to later in life. Luckily he still lives with his parents and they're taking care of him. However, there's a more complicated part to this story...

MY CONCERNS: Our bandmate has been suicidal for most of his adult life. He's struggled with this since childhood and has been on medication for clinical depression for quite a while. He has attempted suicide many times before we met him, and when confronted with us attempting to kick him out in the past, he told us that he has nothing else to live for and said he has no reason not to kill himself. I'm so afraid for him and I don't know what to do.

We were supposed to record our debut album as a band the week after that show and now everything has been put on hold. We have already found a "temporary" replacement but we have not yet told him that it will be permanent. Our guitarist thinks it would be best if they recorded the bass instead of our bassist on the album given the circumstances. I agree but I don't know how to tell our bassist that.

Something deeply concerning is that we've tried talking with him telling him to sell the gun (which is still in police custody until he or his parents claim it) and get rid of it but he refuses... He's also trying to downplay how intoxicated he was and is blatantly lying about how the gun went off. He said it malfunctioned but it was a brand new gun that could not possibly fire unless his finger was pulling the trigger (I know he racked the slide trying to unload it while pulling the trigger)

What do I do? We're all just 20 years old and I have no idea how to handle this and it's tearing into my stomach when I think of having to tell him that his dreams aren't going to happen...

Thanks for reading, please be safe out there...