there is attempted su*cide towards the end of the novel, in the chapter titled Piano Concerto No.27 in B Flat Major.

Al finds out that BWL and MC are together and as a result of finding that out + BWL's prior attempts/feelings of destroying Al/the sub-personality + Al's own lovefeelings of possession towards MC drives Al to shoot himself so that neither of them get MC. He misses his heart, but this was directly witnessed by MC and leads to him being in a coma for a year (+ separated from MC during that time)

After BWL woke up from the coma Al never 'woke up' again but instead showed signs of wanting to merge with the main personality/BWL subconsciously doing little Al things... but BWL was too hostile to him so this never happened. In the end it has Al's eyes showing up for one final second during below-the-neck time (when before, due to MC's view of him as having the mentality of a child Al never openly expressed desire/adult love for MC) before he has one last 'appearance' in the morning while MC is still mostly asleep, whispering to him "I've been waiting for you all my life" (w/ many impacts from throughout the story and MC + Al's relationship!!!!) and finally leaving MC a rosebud and a note below the vase with a poem roughly translated as "If I will see you, it will be years later. How can I congratulate you with tears and silence." That's it. That's the last sentence (the poem ties into a christmas gift MC gave BWL that Al's first awakening ended up getting). I'M SOBBING IF YOU GO THROUGH THE RELATIONSHIP BETWEEN THE THREE OF THEM OMG THE FEELS THE EMOTIONS CRYING TEARS JUST WRITING THIS