This isn't based off his suicide notes note but rather a different one that you have to head canon.

Dear Fabian,

I should be mad at you. I should be furious that you would be so selfish. I should be angry that you would just give up like that. But I'm not. All I feel is darkness, and horror, and guilt. I'm going to be stuck with the fact that you didn't think I cared enough. I'm stuck with the fact that you think I cared so little that you would feel you couldn't even tell me.

You were dying long before you swallowed those pills. You had been dying for months, right in front of us yet we were too dumb to see it. We overlooked all the glances and subtle pleas for help. You held so much pain, so much agony, more than I could ever understand. I would have done my best though, I would have tried to understand, tried to help. But you never gave me the chance. I realize that it was a very dark place for you, but I thought you knew how much I cared. I still care. I pray every night that you ended up in heaven. I pray you are happy. I hope you are comfortable now.

I wish you just would have come up to me and told me. I know it must have been hard, but it must have been harder to end your own life. You had so much going for you. You were the smartest one in our classes (don't tell Mara I said that). You were going to a large university in New York, we were going to get an apartment together, with my school being only a bit farther away than yours. We were going to grow old together, to get married, and have kids. I know we were only 19 but we have, no had, been dating for 3 years now. You promised me forever. But now you're gone and I don't know what to do.

I love you Fabian. I always have and I always will. I'll miss you forever. But I still hope you are happier up there than you ever were down here.

Love,

NIna