My mum is trying to undermine me

[HalfShellHero]

My ds now was dx with ASD ,mild high functioning. My dm has always had issues accepting this which disapointed me but just accepted id not be getting support from her in that area. My husband told me today that when they go over when im at work she grills him 'does you! think hes autistic ' etc and apparently last week she did it again and said that she'd been asking her friend who works with children onthe ASD spectrum and says she doesnt think hes got ASD either or 'presents' that way. im so angry the underhandedness of it all, its almost like she thinks ill be caught out in a lie i did refer or dx him !!! I dont know how to approach this with her shes very much 'I am Right!" POV ...AIBU to want to talk to my DM about how this made me feel?

My entire family and ex in laws are the same, all except for one member, who has always been helpful and understanding. They refused to believe it - he was just naughty and my parenting was to blame. Once he was diagnosed then it became that "ok so he has it but not THAT bad, she's exaggerating". Now he's in his teens and it's sly little digs and suggestions and nudges for him to having the same level of independence as the average teen his age and then knowing looks at each other when I step in to manage the situation. I will be honest and say I dislike and mistrust pretty much all of them now. 8 years of snide comments and looks and pulling me to pieces behind my back has dismantled almost all my relationships and I couldn't GAF. It's made me hard and belligerent and have no interest in maintaining or building relationships with them, actually I can't even be bothered attempting to make new connections either. I suppose it's sad but they only have themselves o blame.