Friend with BPD

This might be a long post, but the general idea of my post is that I would love resources/advice on how to support one of my friends with BPD after a falling out!!

TW// suicide

To begin, J and I met on a social media site and began talking quite frequently. I would say even 4-5 days in, they told me they loved me (in a friendly way). I wasn't sure how to respond to this, but I didn't want to hurt their feelings so I let them say it but I just didn't say it back. Continue on and we are still close friends, we end up calling quite frequently and even watching shows together. Specifically Criminal Minds, which J made me feel like I could not watch with anyone else/without them because it was "our show."

Now, this really weird situation happened where a lot of our mutual friends on Twitter began calling J out for being manipulative and guilt-tripping people. At first, I didn't really believe it because we had always gotten along, and if J did something I didn't like I was open and honest about it. For example, J had a list of people that they hated bc a lot of our mutuals really liked them, and one time J even started a public argument with one of my good friends who didn't even know each other. This left my friend confused and me feeling like J was being very rude, and when I brought it up, J said they only stopped the fight because it was upsetting me.

After a lot of people came forward about this behavior, J blamed it on BPD and made it seem like everyone was being inconsiderate of this. I don't know if this is true? Having BPD is not easy, but does it justify actions like that? I got scared and ended up trying to disconnect from J, at which they completely freaked out and even threatened suicide if I were to leave them. As scared as I was, I didn't want to be stuck in this situation and ended up blocking/removing J from all of my sites and even their phone number. J still somehow contacted me by EMAIL, which is crazy that they had all of this access to my stuff.

After all of this happened and months went by, I started to feel bad and was really worried about how they were doing, so we got into contact again. We talk every now and then, but I still fear that a situation like before will happen and I don't know how to handle it properly. If anyone could suggest some tips or anything for being supportive, I would really appreciate it!

Thank you