Welcome N. - everything you wrote below sounds soooo so very much like my ds13 when he was young:
As far as strengths: he is a very verbal kid. He would create very funny riddles and word plays as a 3 and 4 year old. When 5 he was really into words with multiple meanings and now creates puns (i think thats what he does...ha!) constantly. He remembers everything and learns concepts super quick...and connects dots very easily...a big picture thinker for a six-year old...he is decently creative...and loves living in pretend worlds, playing Legos and Minecraft. He loves to illustrate stories in great detail, as well. He is a very hard worker, rule follower, and people pleaser. Academically he is great with sight words, comprehension, science, and math facts. He is good with mental math, fluency, addition/subtraction.
Weaknesses: He loathes writing. He is a 33 week preemie so we thought it a fine motor skill issue for a long time. He loathes the process of writing...figuring out what to put in the paper and most importantly spelling. He gives up very easily if anything is hard and always has...things that seemed hard for him included reading, writing and numbers. Once a foundation is created (like when he learned his sight words and built up some decoding skills) he is no linger resistant. But introducing a new process seems to be the hang up for him...this reading a book like Life of Fred is a lot of fun for him...or reading about the weather, or making snap circuits...learning how to ell time...excruciatingly painful.
FWIW, my ds is dysgraphic and shares *some* of the traits of the Eides' definition of stealth dyslexia, but I don't believe that he's dyslexic. His reading development was a bit quirky, but once he was reading he was reading way above grade level and that's continued throughout school so reading really doesn't seem (on the surface) to ever have been an issue. OTOH, he has a very similar WISC profile to your ds, and fine motor dysgraphia has been a *huge* challenge for him. That's not saying your ds is dysgraphic - there are many different reasons that you might see a dip in scores like he has - but what it is saying, to me, is that you need more information to understand what's up, before you're truly going to be ready to come up with a plan.
There are two places you can refer to for more information on your own: the subtests on your ds' achievement testing, and your knowledge of what you've seen re your ds and academics - where he performs well, where he struggles. You can also look for signs of either visual or fine motor challenges in everyday life - did he have a challenge learning to tie his shoes, for instance.
A third resource is to read everything you can on dyslexia, dysgraphia, stealth dyslexia etc and see what might fit or not fit with what you've observed over time. Some clues are going to go back to early childhood too.
The other thing I think you will need (and this is just me, a non-professional parent, so take it all with a big grain of salt:))... is additional testing. Our ds' neuropsych testing included tests of visuo-motor integration, executive function, and fine-motor functioning - these tests helped tease out the reason for the large dip in processing speed.
Another thing for you to do is to review exactly what skill is assessed by each subtest of the WISC. You've mentioned the low processing and dyslexia somewhat intertwined, and processing speed does sometimes test low in people who are dyslexic or have reading challenges - but these subtests are tests that can also be highly influenced by slowness in brain-fine-motor integration or by a visual challenge or by simply being anxious about being timed (most of the other WISC subtests aren't timed... I think one of the PRI subtests is but can't remember which one). One way to separate out is there a reading challenge is to look at the reading achievement subtests - are they consistently low or is the fluency subtest lower? There are different response types required on the subtests - students like my ds who have a fine motor challenge but *not* a reading challenge may have a score in line with their IQ score percentile on a reading achievement subtest that requires a verbal response and isn't timed, but will have a lower than anticipated score on a subtest that requires a written response, and an even lower than expected response on a subtest that requires a handwriten response and is also timed.
I hope that makes some sense - I'm writing this all out in a bit of a hurry!
It is possible achievement is lower due to exposure and interest. He did go to preschool and we have always read at home. But he was never interested in learning to read and we have never jump started a skill (preferring to wait until it is introduced to same-age peers).
I thought the same thing re my ds when he had his first neurospych and his achievement scores were very scattered and much lower than I had expected them to be. It's possible that's what's happened, but you've mentioned behaviors re writing etc that indicate there *could* be something more going on. I'll also add that my ds never seemed interested in learning to read and we just thought that was all personality - he was into legos etc, building things. He was so advanced verbally and able to express such complex concepts at an early age and always asked such advanced questions we just chalked up the things he *wasn't* doing to gifted-kid quirkiness. Instead, they were signs of things that were real struggles and it just took school experiences to bring it all to the surface. Everything was fine when he was still at home and in preschool because he *could* choose what he did with his time and we (parents and his preschool teachers) didn't push any type of skill development, we were following his lead.
The other thing I wanted to mention was my 2e dd - she's younger (9) and we are still trying to work through how her challenge impacts her and trying to define exactly *what* it is, but she has had a very tough time learning how to read and is very frustrated by it. In her case, she has a weakness in her ability to associate sounds with symbols - she can understand and comprehend at a high level when she listens to audiobooks etc, but not when she reads from text. This has *nothing* to do with your ds except for testing - she's been through two dyslexia screenings, and one very thorough reading assessment. She's had the CTOPP and has similar type range in scores, but she's also had quite a few other reading-specific tests, including Gray oral reading and a bunch of others that I can't remember the names of but would be happy to look up if you'd like to know. If you think you're looking at stealth dyslexia or some type of reading challenge, I think it would help to have the breadth of these other tests - and the place I'd look for them would be through a reading specialist. In any event, there are so many different types of reading programs that I can't imagine it would be useful to dive off into one direction (program) without first having a really good understanding of what the challenge really is.
Lastly, once you have a good understanding of what the challenges are for your ds and what accommodations + remediation he will need - I would share it with the school - and I'd share now, not wait another year. The sooner you start advocating for accommodations in school, the better for your ds. The school district might not be able to provide your ds with all of the help he needs (we've relied quite a bit on private therapies etc) - but it's important (jmo) that they know early on that he has needs. It's also important to try to figure it all out so you can help him understand.
Gotta run - I am sorry I didn't have time to be sure this made sense - feel free to ask more questions!
Best wishes,
polarbear