Little legal recourse against rude HOA ex-president

Question: I live in a large subdivision with 727 homes, and we have a president who treats board members, homeowners and others with rudeness and disrespect. We also have a large management company that witnesses the tone of his messages, and his illegal negative consent votes, and does nothing. At the last meeting, he walked out, and I was elected president.  The ex-president sent me the below letter. If you received a letter with these types of threats, what would be the proper recourse?    Read the Q&A………..