Before anyone can help you, you have to describe the problem without using conclusions like "abuse," "harass," "discriminating."
That said, an HOA has no business having keys to peoples' homes or entering them without permission.
No one can tell whether the former president's continued role is unlawful without more details and an analysis of the HOA documents.
In Georgia it is not uncommon for the HOA to have keys for units in a condo or townhouse for the limited purpose of attending to emergencies, such as burst pipes in winter, or fires, etc... But otherwise, there is no right to access without advance notice and a valid reason (ie pest control spraying). This must also be specified in the covenants. The Board cannot just one day decide they want to start inspecting units. The Board's authority comes from the covenants and they are not supposed to supercede that authority. The bylaws should set out how board members are appointed if all the positions aren't filled at an election or if someone resigns. They may also have a means for removing a board member. Take a look. And if enough of the HOA members are in agreement with your way of thinking, maybe a group of you could get together and hire an attorney to force the board to begin acting appropriately, or to remove any board memebrs who have acted inappropriately. If any officer or director is acting outside the scope of their authotrity, you may have other causes of action, such as trespass, which you may want to speak to an attorney about.
This is not intended to be legal advice or create an attorney-client relationship. If more information is needed, you should consult with an attorney in your state regarding the specifics of your situation and the options available to you.