Flooded: As someone with BPD I find it kind of demeaning that you ask if cats T has BPD in relation to how she acted because I know I would never treat someone how cats T did. People with BPD are not characteristically outto hurt others and it tars everyone with the same brush and causes stigma when people do.

Cats: Massive hugs! I think a big point in her message that is very telling that it is definately not all your fault at all is the fact she said "I am angry at myself for letting this happen" - and that is a fact, she has encouraged the type of relationship you have with her and is now taking it out on you.
If she wants a more boundaried and professional relationship then she needs to set and hold more boundaries and be more professional - swearing at your client and being so rude is neither! She is not setting any good modeling for you to follow. I can understand your anger at her. I think you have attachment and dependancy issues and she has actually made them worse, not better!
She would be in major trouble if you reported how she speaks to you alone, never mind the boundaries that she crosses. How can she expect you to keep boundaries when she doesnt. Any good therapist would have not called you back when in that state of rage because they knew it would harm the client. IF she felt that way the professional way to respond would have been to either call back when she was more in control of her emotions or not call back and speak to you at the next appointment. This therapist really has a nerve to call herself a therapist and treat someone this way. I am not saying that perhaps you have no ownership in the situation but I think she has made a lot of mistakes which have lead you to be even more vulnerable, not less.

Cats I am so sorry your mum is unwell but I hope it is treatable and that she can beat it!