My heart goes out to you, as we have both walked somewhat the same path. [We have a grown daughter who is autistic, and a grown son with ADHD and retardation, and both with hearts of gold!]
First, good for you not only for observing and discovering that your son is a hands-on learner, but also for finding a hands-on math program for him. The fact that he now loves math shows that you are right on target, and have found a way to help him learn while enjoying learning. Congratulations, Mom! You have already found part of the secret to motivating him.
A good approach to social studies would be to utilize all the hands-on discovery and learning suggested in the Lesson Plans. For science, you might lean toward the hands-on activities and experiments, as well as helping him find and select colorful books on the topics from the library.
There are also wonderful computer-based geography, math, science, spelling, and language programs that are disguised as games. Online searches will turn up so many that it's hard to choose! [Our grandkids love the geography puzzles, for example.] [Don't rely solely on the games, however, but use them to supplement.]
For those subjects that are a bit 'drier,' a chart could be set up with a reward such as an extra half hour at his favorite educational computer game, or extra 'recess' or some such if he finishes the assignment within a certain period of time. [Perhaps fifteen minutes, with a kitchen timer set for that amount of time.]
Keep 'drier' lessons short where possible, even if it means assigning half a page in the morning and half a page in the afternoon. You might also start the day with the drier subjects, while your son is fresh!
You are also very, very wise to go back to the basics on everything. It is always best to start at the beginning, as the child will usually forge ahead swiftly. When they begin to slow down and struggle, you then know exactly where the learning stopped and where they need to start to catch up!
Now, this is very personal, and it may or may not fit your circumstances, but I offer this as my own experience:
You mentioned an inability to focus. No matter how much our son liked a subject or activity, he simply couldn't focus. He was obedient, didn't whine, and stayed in his chair. He was cooperative. However, he twiddled the pencil and erased holes in the paper and drew pictures and twisted his shirt and looked up at every sound and motion and rocked the chair until it fell over. We were reluctant to have him on medication, too, but finally agreed to try it. Suddenly, he could focus!! It was absolutely amazing. He was so proud of himself, that he could now actually do his work.
Now, not every child needs medication, and I think sometimes the schools try it as a first option when it should be the last option. Sometimes what the children need is a little help with self-discipline and obedience, as that can be harder for our kids, too. [Dr. Ray Guarendi's books and tapes are absolutely wonderful in this regard.]
What I've found is that having a parent who observes the child's behavior and takes notes on how the child is reacting is the biggest aid in deciding whether or not the child would benefit from medication. Does your son have to be moving constantly, either his whole body, or maybe just his feet, hands, or his head? Does he look up at every sound, or when someone comes into the room, or sneezes? Is he a lot 'busier' than most children? If so, a good test would be to observe him at his work for a few days, take notes, and then perhaps try him with the same situations and subject, in the same place, for a few days on medication. If the medication will help him learn, you will know by observing.
Right now, he is learning to be at home and to be homeschooled, so it may take a month or so for things to settle down for him. If at that point it's still a struggle to get him to do his work, counseling might be of some benefit.
You're on the right track, Mom!
May God bless and guide you, and the Holy Spirit grant you special wisdom. He is faithful!