Adhd husband and his original family

My husband and our second daughter have ADHD. Daughter is doing well because I got her therapy and accommodations from a young age. Husband is very successful entrepreneur because he surrounded himself with people to keep him organized, admitting he "files by piles".  After 29 years, having raised two beautiful and successful daughters, despite the ADHD challenges, with me managing all the details, I am suddenly, unexpectedly attacked by his siblings with crazy notions they are projecting onto me, but are actually in their own heads. I have stood up for the truth, but  ADHD husband keeps making excuses for them. He was bullied as a child, and put down in the pecking order in his family while growing up. Is there any chance he will ever stand up for me? He hasn't yet, no matter the occasion, as he is unable to confront anyone. Is this fear of confrontation a part of ADD or something else? Will he ever be able to stand up for me when it requires a confrontation? So far the problem has arisen with his coworkers, family, and a neighbor who backed into my car and drove away without leaving a note. Meanwhile, my family treats him like a prince. Would welcome any thoughts about this.