People on the spectrum with high IQ but lower cognitive processing speed, what things help or hurt you in academic or social environments?

I'm looking for ideas to help understand and assist my 7 year old kiddo who scores "low average" (37th percentile) in processing speed but very high in other cognitive categories (90-98th percentile).

He struggles with writing, making choices, identifying and expressing emotions, emotional regulation, and working/answering in a timely manner.

I think his brain just doesn't work fast enough for how intelligent he is. I want to do everything I can to support him and advocate for him in school.