Self-care, mindfulness, self-care and more self-care.
You might worry about the next fight, you might worry about the calm, partly because it activates guilt too. You wonder if you are to blame, did you push it too far, are you a bad daughter, are you what he says you are ..
You are not.
Shut down those critical and harmful voices in your head.
Here is a nice website that can likely help:
https://self-compassion.org/category/exercises/Self-compassion for yourself. No guilt. No shame.
If he is calm, if he doesn't call you out and act out then now is a good time to look inward and take care of yourself. To assess your own reactions TOWARD yourself. Look at the blame you put on yourself, your own tendency to gaslight yourself. And give yourself sympathy, because you have been through a lot.
Don't underestimate the amount of self hatred you internalized, simply being raised by a parent with BPD.
Don't reach out to him, don't try to appease or prevent.
Turn your attention back to yourself. You need you.