Is there some reason you have to hurry on the house (multiple siblings clamoring, for example)? I would make some sort of plan for my life in the next year, goals like getting a job and getting the house cleaned (whether by you or others) and work on them in my own schedule.

Were the sociopath bosses the only people in the company you worked for? I would just give a phone/name of someone else in generic forms you have to fill out if you can. You can say/pretend you thought your boss had left, just give the "personnel" name/number, etc. All they can say nowadays to avoid suing is to confirm what they are asked by people, "yes, they worked X date to Y date", "Yes, they got $ salary" stuff like that. If you are talking reference, I wouldn't give that guy; give a customer that you liked and that liked you, that sort of arrangement. They "know" you and your work. If it was only that guy and you, I'd put the company name and not fill in the rest; in your resume you just put company name and your title; they can try to find the guy if they want, they probably won't and when they do his attitude toward you (if he wants to risk being sued) will probably tell them why you did not give them the info.

I would not bother hiring a PI as there really is nothing they can find. It's not like phone calls are recorded or anything and people who do not hire you are not going to say it is for that reason, etc. My boss at an association I worked for was sued by a black man and the guy was all but laughed out of court (since there were multiple blacks working for the association who were quite ready to stand up for my boss and against the black man). So, even if you get a lawyer to try, there's no money in it (especially after you pay a PI and a lawyer :-) and usually it is just to get one "reinstated" at a job, not to get damages or anything. If you were not hired, there's no event there; people can give any/all reasons for not hiring you and not any way you can prove you would be a better choice than who they chose so that they clearly should have chosen you but did not because of this one guy's reference.