Harassing HOA and unwritten rules

[David Robrecht]

so long story, but I will try to make it brief. Parents are retired and we're in the market for a condo in which they could live in for the winters and rent out via weekly/airbnb during summer. They found a nice condo by the beach in a small 10 unit building with no rental restrictions. After closing and moving in a new neighbor and them were talking and when informed of my parents plans, they informed them that her husband was on the HOA board and would never allow weekly rentals. Her and another neighbor then proceeded to mildly harass and bother them constantly about anything and everything I.e. Making noise when closing outside gate and coming out and just being nosy if they were eating on the common area patio amongst other little things. My parents decided to sell and just cut their losses rather than fight the board and deal with them. During an open house they had yesterday the neighbor came to it and informed the realtor that she's wants to tell all potential buyers that there Is a minimum 1 year rental restriction even thought ccr says none. Also unit on other side rents to traveling nurses who may only stay for a few months to 6 months at a time and when realtor stated that fact to lady she said yea but that's the the other side of the building (10 units, 5 on west, 5 on east separate common areas). My question is what is the best way for my parents to handle the situation? The HOA will never put a written rule on restrictions because it will decrease property value but they have enough power where if my parents were to fight it they may change ccr. Also what do we do about neighbor who feels she has a say on every thing that happens on her side of building? Thanks