How do you deal with family that doesn’t “believe” in autism? 😩🥲

So, I know it’s fairly common for the Boomer generation to kind of disregard mental health and neurodivergence of any kid. At least in my experience, this generation thinks it’s more of a willpower thing, like there’s no depression, you’re just lazy. Suck it up. My parents basically ignored my problems and CPTSD and anxiety I had as a child from being sexually assaulted, until it resulted in me being so severely agoraphobic that I couldn’t attend school without fainting. Then they “had” to act, and I was put on a plethora of drugs until I no longer cared. No therapy. 🫠 I know my story is common and familiar.

Anyway… my son is autistic. My parents refuse to hear it. They say he’s just “different” but “still normal.” My son was talking to my dad on FaceTime (they’re VERY close and talk every day). My dad said “what are you doing today?” And my son responded “I’m going to see Ms. Hannah”. Ms. Hannah is his occupational therapist. My dad grunted and shouted at me “how long does he have to keep doing this crap?” I was like “indefinitely. It helps him.” My dad responded “bullshit, there’s nothing wrong with him.”

It’s the complete denial for me. It just aggravates me so much and I don’t know how to respond until like an hour later when I’ve had time to stew. Both of my parents and my in laws refuse to believe that he is autistic. My in laws go as far to say he’s “like this because we don’t spank him.”

How would you handle this?