I had to go visit my sister at a facility after one of her suicide attempts. I would not bring anything now, just ask the nurses/care providers about what is allowed.
I could not bring flowers to her as she might try to poison herself.
I could not bring a spiral notebook as she might use the wire to hurt herself. Etc etc.
Just bring hugs. Be emotionally prepared to be very overwhelmed-- there are a lot of very hurting people you might see/be in contact with. I visited her three times while she was in the facility. She wanted to talk, so I listened. She was angry and wanted to blame one person in her life, then the other, and I stayed silent. I was there just to be present, not to be a therapist.
Your friend may be angry that their suicide attempt failed. Your friend may be outwardly angry at others instead of being able to focus on their own part in how their life got to where it is. This is a time that I would not even suggest 'reflective' listening, but just being present, nodding, 'hmmmm'... as responses. Your friend may be angry or explosive or really sad. He's going to have to figure out, over the time he is in care, how he wants to address his depression. Right now, life is hurting so very much. If you make any statements, just try to be genuine and own them. Instead of reassuring 'hang in there, you'll get better' you can say "Wow, I would have been so sad if you were gone from my life".... something he cannot argue with. I would also leave out any "it was God's plan for you to still be alive" type of reassurances out of it. The guy likely feels like there is NO game plan for the future and is going to need a lot of support to just get to that point of putting one foot in front of the other on a day by day basis.
Lastly, give yourself some time to process this later today. Allow yourself to cry or grieve or feel bad for a while, and do take care of yourself. I found those visits to be emotionally draining and rather devastating sometimes. I wasn't in a place to go do something fun or be bright and cheery for others later on. You can ask him what he needs, before you go, and then be sure to check with the nurses or helpers if those items are allowed before bringing them.
Hugs. Sorry.