Does "bootstrapped" mean self-funded or that you have only taken seed money? I think you need to call on a higher power but if you don't have a board you can call on you might have to make sure you are leaving (when the time comes) on the best possible terms.

throw him under the bus. do not pull any punches or try to cover his mistakes. i'm not saying to air your dirty laundry to customers and others, but don't treat him favorably in any convos you have ... if he derails a customer relationship, so be it.

if it's really as bad as you say, that you need a miracle, you're done. make sure that you leave with some dignity. don't tolerate insults. you can be calm if you keep in mind that it says more about him than it does about you. "that's unacceptable, do you want to restate that?" and then if there's no correction, "this isn't productive" and leave the room.