At the heart of your question is a matter of fairness and law. As a broker it appears you are in an unfair situation, where one family has unreasonable control of the association. Regarding the law, you should take this up with a local attorney. Not the issue of the windows, that's only a symptom, but the way the association is set up where this one couple has unreasonable control.
A real estate attorney can review your association agreement and advise you whether it's legal or not and how best to proceed to bring it into a more fair arrangement. Sorry I can't be more helpful than that.