I did fill my form out for my mum but in my case my mum was stood over my shoulder literally nodding at everything I was putting.
My nan on the other hand (whom we live with) was in denial for a very, very long time.
All the people diagnosed with ADHD and autism in our family were diagnosed early and were young white boys with the traditional hyperactivity, delayed speech, not recognising their name being called, and intense and strange interests.
To her I was a very normal child, because her normal children behaved the same way and grew up to have BPD, OCD and schizophrenia (which is sadly probably due to trauma from unmet need in childhood). She also couldn't understand how hyperverbal, hyperlexic, perfectionist, attentive little me could be diagnosed with the same condition as my then 3 year old non-verbal, inattentive, bouncy, risk-unaware, illiterate little boy.
@0psiedasiy is your brother able to be your history informant?
It only has to be someone who can validate your struggles have been present since childhood, not necessarily a parent.
OP I'm really sorry about the burnout. I've been through it a few times. I have an appointment on the 10th to talk about autoimmune conditions which can stem from prolonged and persistent burnout and I wouldn't wish this on anybody. Please look after yourself, and I know it can feel weird putting your needs first as it's such a sudden change it can be easy for people to judge you on a "well you were fine before" basis, but keep gathering all of your strength to advocate for yourself. It's really hard when your parents won't accept it because they don't know how to behave around or treat disabled people.
I'll hold my hand up and say the first time I had contact with someone in a wheelchair I was actually 16, and I didn't know what the etiquette was, know why she was in a wheelchair, what her capacity was and it made me behave really weirdly around her. Then she talked to me, and it's like this balloon popped, all this overwhelm I'd felt disappeared, and we became really good friends and she didn't mind me asking a million questions about wheelchairs, wheelchair users, what their challenges were, what she loved to do for fun etc. I imagine the feeling I had before she talked to me is what a lot of older people who have been forced into a society where segregation was normal do because 16 years is a really long time where disability isn't normalised. But for them that bubble of overwhelm and confusion just gets bigger and bigger and everybody is scared to pop it incase it let's off a really loud bang.
If I didn't have an understanding mum, but I still had a loving mum, I would probably still use things like disability aids such as ear defenders etc. Round her, and if she asked why I'd just say something like "oh the doctors have said it'll help reduce my tinnitus/stop me getting migraines so I'm giving it a try". That way it's not a lie, but it isn't outwardly othering yourself.