You don't have to physically take the phone away, since he's on your account, can't you call your service provider and shut the number down?

Also, you didn't mention your daughter before. Honestly, I would steer clear of any physical interaction with your father at this point, given that it is possible your daughter may become entangled. So, no, don't maintain a presence.

You could still offer assistance and support to your mother from a safe and reasonable distance, but you should maintain adherence to priorities and your daughter's safety should probably be at the top of that list. [I am making the assumption she is a minor an so dependent on you though] Meaning right now she should likely have zero contact with someone as erratic as your father if he's hitting family members.

Sorry if I'm telling you what you already know. I don't know, sometimes I need to see things written out for me in black and white before I realize what I want to do.

ETA:
And also- it's not slinking away and hiding. I think the idea of exposing yourself to continual hurt and abuse based on the idea that someone is ill, therefore not responsible for their actions is pretty silly. Like, they are screwing up because they are manic but you should accommodate abusive behavior?

No, you make an appropriate decision for yourself, which sometimes means extracting yourself from a situation entirely. Self preservation is a natural instinct.