Should I forgive my best friend I've had most of my life?

Katie • Lover of lipstick, pasta, and Paris.
I've had the same best friend for most of my life - he and I grew up together and both came from rough backgrounds. We basically raised each other and created each other. We both defeated our circumstances and went on to be very successful. After college, I moved many hours away and he stayed in the area we grew up in. Not long after I left, he hit a rough patch and lost everything. 
I would drive up multiple times to see him and still be there for him. Meanwhile, for the past few years, he would always make plans to come visit me (i.e. birthdays, other important dates) and ALWAYS come up with an excuse not to come literally right before. 
Finally, I stopped trying as much and while I was living in Paris, he messaged me and owned up to the fact that he'd been a terrible friend and I'd always been there for him. He said he'd hit rock bottom and tried committing suicide and was now in counseling. He said it was helping him realize I've always been there for him and he didn't want to lose me. 
I gave him another chance, because hey - we're best friends and always have been. I moved back to The States and he took time off of work and swore up and down he'd come visit me. Right before, he cancels. I decided I was tired of getting my hopes up and constantly being let down by who was supposed to be my best friend. 
Fast forward to just recently, he said he tried committing suicide again and also cheated on his boyfriend. He said he's found God and is turning over a new leaf. I didn't reply. He started sending me very strange messages such as, "How does holding that grudge against me feel? Can't feel good. Your CONTEMPT is showing! You can't handle the fact that I've given everything to God and am holding up a white flag!!! You're not that strong, darling. It's actually laughable." Very weird stuff. 
I still didn't reply. 
I'm moving to another country next week and invited him to my going away party to be polite, not expecting him to show up. Instead of RSVP'ing, he sent me another message saying he loved me and wanted to catch up. I didn't reply because I was at dinner with a friend. Not even 5 minutes later, he says, "It's fine - I get it. Thank you for making me who I am. I hope I never hurt anybody like I hurt you." He then proceeds to delete me and block me from all social media. 
Seeing as I'm leaving, this is kind of my view right now. He's been my best friend for so long and I love him - shouldn't love be unconditional? Sure, he's had issues, but I'm tempted to text him before leaving and tell him I forgive him and I'm here for him no matter what - that's what best friends are for. 
What do you think?