Welcome, Laliqbaila!

I'd like to join the others in welcoming you to the discussion forums. From what you've written, you and I (and many others here) have a lot in common. First, we have the "light bulb" moment when we first find out about BPD - and it explains so much. Then, we reach out to others for support, as you have. So, welcome, you're in the right place.
Thank you for sharing with us what you have thus far:
It feels like he is in another world and I cannot reach him, yet he tells me he needs me, then every conversation degrades into hours of ranting that everything going wrong in his life is my fault. Over and over.
I hear you. This sounds incredibly tiresome and frustrating. What do you do or say to your son when he goes off on a rant? Does anything help? What makes the situation worse?
Please let us know how best to support you. Keep us posted on how things are going for you.
Hang in there.
Keep writing, keep processing, keep learning.
-Speck