Now it's time to celebrate all the things you are doing to enrich his strenghts! You are doing a great job here - these are exactly the sorts of things I would suggest for a kid with 135 Perceptual Index score. Yippee!
What I particularly like is that you were willing to let him try those difficult LEGO sets even though the age on the box was clearly well beyond his years! Most parents would be stopped by something like that, but you persevered - Go YOU!
I am talking to a math tutor who is a math professor and works with gifted kids. He is a gifted person too and he said he was slow himself so he understands DS. Hopefully DS will like him when he meets him next week. This might give him the enrichment he needs and bring back the love of learning.
We are also switching him to a new school that promises to focus on STEM. He is excited about that since they have clubs like Lego FLL.
He loves building stuff like Legos. He assembles kits that are meant for teenagers in a few hours.
He loves doing puzzles does not stop until he is done with it.
Currently he is building a train set meant for age 14+.
My son enjoyed electronics kits also. And a book
http://www.dangerousbookforboys.com/which might give him some woodworking project that might be a sneaky way to add some physical activity to his life. My son built a wheeled cart that he would drag up the hill and then scoot down on with his friend. Not the sort of activity he would usually be interested in, but because he had built it with his dad, he was.
More soon...