Clients often have the strangest notions. They actually think that if the law says something, then the employer must do what the law says. I have to break the news to them: employers can ignore the law. Yes. Employers can ignore the law if they do not mind the consequences. Employers do it all the time. Seems to me employees sometimes forget they work for an employer. If the boss says they will not accommodate you, then that refusal is the "law" until you can file a lawsuit and obtain a ruling from a judge.
So, yes, if you file a lawsuit against your employer and you still work for the employer, then, guess what, you still have to ask the boss for time off to attend a deposition. You still have to ask the boss for time off to attend a trial at which the boss may also be present. The employee’s lawyer cannot give you time off. You do not work for your lawyer (actually, its more the other way around).
Continuing to work for an employer you have sued can make the working environment very tense. But, remember, if the employer is halfway intelligent, they are even more nervous. Because the intelligent employer knows that if s/he says anything halfway inappropriate, then that could become the subject of another EEOC charge or worse. So, remember you may be nervous. But, your boss is even more nervous. Cut your supervisor a little slack and you will benefit in the long run…..