Hi Glynnis,
Welcome and hello
My partner's D19 is also transgender. She's been dx'd bipolar and meets 6 of the 9 criteria for BPD, comorbid with dependent personality disorder.
I am so confused by the transgender part when BPD is involved, to be honest. I see identity disturbances and that is more confusing to me than what gender she identifies with.
It is ok to acknowledge that you cannot pay for the reassignment surgery. This is your daughter's goal and she can work toward it. Perhaps it will take some effort on your part to validate her, while also learning some of the skills to coach her toward competence. I know it's hard. When a child threatens suicide, it is paralyzing.
My BPD sufferer has pushed me to the limit this summer (she's only with us for another two weeks), and I was married to a BPD/bipolar ex husband, and have a son with mental illness as well. What I learned is to take care of myself first so that when I interacted with D19 I could be in a place of compassion and empathy, and apply the skills I was learning. When you are compassionate and empathetic, it helps to elevate the BPD sufferer's skills toward competence. The struggle is to be able to stay in that place when you feel like all you hear is complaining and abuse.
Change is hard, too. If you have felt weakened by the abuse and feel the strain of the relationship, there is often an initial push back as boundaries shift.
We're here to help walk with you.
You're not alone.