lzcuchaca, welcome.

It's not just overwhelming to learn about BPD, it's pretty common to feel a sense of urgency to do something. Hang in there. You have a new piece of the puzzle.
My question is what should I do next? Should I try and meet with her therapist on my own and share all of this with her? Should I encourage her to find a different therapist since her current one seems to be enabling some of her behavior? (She might be doing so because she isn’t aware of the the possible BPD).
There's a chance the therapist already suspects or knows about BPD, esp if your wife exhibits clear behaviors. It's also possible that your wife is choosing what she feels are supportive statements and discarding any of the T's challenging statements.
Do you think your wife would be open to allowing you into her counseling sessions? Some people see this as a supportive step. Others might feel like you're trying to encroach on their support system.