I just wanted to suggest this Twitter chat. It's mainly for those with BPD or who can empathize with some of the symptoms, but carers or anyone can follow the conversation and it might shed some light or offer up some tips.
The chat is usually hosted by either https://twitter.com/BPDFFS or https://twitter.com/CarlDunnJr and is on every Sunday between 9 and 10pm. The chat will usually begin with an icebreaker to help see who's going to be joining the conversation and to find common grounds with people. The icebreaker can be anything from your favourite sweet or something you're grateful for!
The topic of the conversation changes each week and you can usually find out what it will be a good time before the chat so you can decide if it's relevant to you, something you're interested in or if it would be too triggering.
There's two rules with the conversation; you always write #BPDChat on your tweets that are part of the conversation so that everyone in the chat will see and if you think your tweet might trigger anyone then you must put 'TW' at the beginning of your tweet for 'trigger warning.'
After my first #BPDChat I found myself with a lot of new followers and also, friends. It was so heart-warming to read people agreeing with me and saying 'I get that too.' I felt less alone and I think this would be felt on an even greater scale if you were in the community.
My one tip for joining this chat would be to have two Twitter tabs open; one that is set to your 'notifications' - so you can keep up with direct responses to your tweets, and one tab for the results on searching #BPDChat so you can keep track of the entire chat.