"I asked him to please stop with the bullshit..he acted like I was being ridiculous..sayin he was just kidding..blah blah blah...he's done this me as long as I've known him.." Gaslighting. I hate it when they do that. I have learned a lot about gaslighting and narcissism in the past year and a half, and how I was subjected to it for 18 years.
Run.
Run away.

I know what I would do and did find a new best friend. Best friends don't treat me or you with disrespect. I found after 10 yrs hanging together he began to critize me more and more and bragging about how much better off he was than I. I overlooked it way to long and finally just got fed up , I began to realize it was like being in a bad marriage I had to walk on egg shells, afraid to express my opinion and when I did it was always wrong. My dad treated me like that I be damned if I was going let somebody else treat me like that, I'm an adult not a . So I can relate.

Hey, it was my birthday yesterday too. So happy birthday to us both. I had a good day, my friends treat me well and I am truly lucky. You need to be aware that you are not in any kind of way responsible for anybody else. He needs professional help and you are not the one to give it to him. Why are you putting up with that, all that misery, stop having anything to do with him, you are not helping him in any kind of way, just enabling him to be a jerk. It's up to you, you want to be trodden on than keep him as your friend, if not. Don't tell him just text him that you will have nothing to do with him if he keeps it up and stick to it. Don't answer the texts if they are rude or defamatory. It's not easy but it is doable. Perhaps you are doing him a favor by ending the friendship.

Rules, Boundaries, Limitations.
If he knows what yours are and disregards them? That's a problem.

Sure our closest friends get to cross those lines when something awful happens to them - but for him it sounds like awful is a lot of the time.

You have to decide if there is any reward for you in this relationship any longer. Friendships aren't one-sided.

I too have a close bi-polar friend for 35 years. Once I had to exclude her from my life after she hurt me over a friend of hers i briefly dated. That lasted 4 years. Recently blocked her on FB and later reinstated her. She was there for me as I fought for my life however, and since I've moved out of state we still talk on the phone and are friends on FB.

Happy Birthday xxxx

Happy belated birthday, for what it's worth.

You should quit letting the guilt of being his only friend control you and bid him adieu. You're being manipulated by him, whether it's intentional or not.

That he has no other friends should be a huge red flag to you about how he treats others. By playing his game you're saying "hurt me instead of you", to your detriment, and that's not fair to you. You're enabling his bad behavior, and could be preventing him from getting the help he really needs. Some people need to hit rock bottom before getting help - don't hit the bottom with him.

Happy birthday!

The only person you can change and control is yourself. I suggest you see a counselor to learn to stop rescuing people and set healthy boundaries for yourself.

Surrounding myself with positive people improved my life.

After her third divorce, my friend was stuck playing victim. Constantly complaining, she bitched and moaned, blaming others for her problems. This went on-and-on. She exhausted me.

"Let's talk about positive things," I suggested. Nothing I tried worked.

Finally, I wrote her a kind letter, saying her negative talk was bringing me down. I asked her to focus on positive events instead. In response, she cut me off.

Although I felt sad about losing a friend, it's a relief.