My mom seems ashamed of my autistic son

My son is 5 years old and was recently diagnosed with high functioning autism. He is a smart, brilliant and caring little boy and communicates very well.The only thing he really struggles with is behavior like not being able to focus on something for long periods of time and wants to try to run off. However I can't help but feel like my mom is ashamed or embarrassed that her only grandchild is autistic. When she does talk about it she always asks about what kind of treatment he can get like it's a disease that can be cured. And a couple days ago we went to visit some family and on the way there she asked me not to mention to them about him being autistic because she doesnt want them "gossiping" about it. My family loves my son to pieces. I know they would never treat him any differently. I just don't know how to talk to her about how it makes me feel when she says stuff like that because she can get very defensive and offensive when you try to confront her about anything. What should I do?

If she brings it up again i would say “I don’t think they’d treat him any different, they all love him to pieces” & see her reaction. Sometimes you don’t have to come out and ask/say “are you embarrassed of him?” Just ask her a question that will make her go “woah, why am I saying this?” If she continues, I would get to the point where I’d just straight up ask her, there’s no reason to hide it especially from family. There’s nothing to be ashamed or embarrassed of.

Just tell her to back off and get educated. Pretty simple. If she gets offended oh well. She doesn’t care if she offends you so why should you.