Dealing with a person with BPD is exhausting by nature. By the nature of your post, I can surmise that you want to work on ways of communicating better with him. But before you can do that, it takes some knowledge of BPD and how he views the world.
A couple of things about your post struck me - the "no win" situation. Bingo. That's the way dealing with a pwBPD typically feels. No answer is the "right" answer. No response will soothe him. That's all typical. He has a strong emotion about something, and he interprets or misreads your words in order to support the emotion he has. Your goal is to validate that he is upset, state what you want, and leave it at that. If he continues to be upset - that's his problem. The more you justify, defend or explain, the more he feeds that into his distorted view, and the more he gets upset. And next thing you know, you are in a conversation that lasts hours until you are both hurt. You know what reality is. State it, state what you want, and then move on whether he wants to or not.
"Sweety, the car had a problem today, so I took it in as to avoid potential further damage. I will let you know when they are done." Of course, he will blame you, and you can say "I'm sorry that our plans for tonight may be cancelled and that you feel upset about that, but there is nothing I can do about that right now." After that, you have told him all he needs to know, and if he is upset, that's his problem - you can't fix that no matter what you say or do.
A second thing I noticed - people with BPD tend to have big problems with open ended plans or indefinite answers. They spend a whole bunch of time trying to figure out the future as to ease their anxiety. If you can't tell them exactly when you will be somewhere or exactly when something will happen, they are uncomfortable until they eventually crack. I've seen this over and over with my girlfriend. She's completely incapable of being happy today, so she wants the future to happen RIGHT NOW. That's the same in your story - because the plans suddenly changed and now he doesn't know what he is doing tonight, his anxiety went through the roof and he blew up.
You may want to check out these workshops on communication with a pwBPD:
TOOLS: S.E.T. - Support, Empathy and TruthHow to stop circular arguments Both have been useful to me.