On report it says significant intellectual disability. What does this mean?

[parasiticworm]

Also it says extreme low range on the adaptive functioning test. My working memory scores are poor which means your ability to intercept, organise and think with visual information is limited.

I also lack capacity to manage my finances. Have a court ordered Deputyship.

Would this letter help me continue getting benefits if my support workers sent it in?

What exactly does the above mean?