From the test scores you listed, the comments from the OT and your description of him falling down a lot, my first opinion as an OT is that he has low muscle tone which is impacting his hand skills. You need good proximal stability (aka: core strength or trunk control) in order to develop good hand skills - especially higher level skills such as in-hand manipulation and handling tools (ie: pencil). What does his pencil grip look like? When he falls does he often make a joke about it or seem like he almost throws himself on the ground as part of play? Does he often fall and then say, quickly, "I'm all right!"
When he uses scissors does he pull the paper and scissors close to his body? Does he hold activities such as lacing cards, stringing beads or crafty type things close to him when doing the activity? Does he wrap his legs around the legs of the chair he sits on or sit with one leg sort off the chair so that one foot always touches the ground, if the chair is too big? Does he sit cross legged on the floor, "w-sit" on the floor or prefer to sit in a chair? Can he put his shoes and socks on in the middle of the floor without leaning up against something?
Does he have difficulty with eating at all? Is he a messy eater or take really small bites? Does he limit foods to certain textures or temperatures? Does he handle fork, knife and spoon appropriately? Can he blow out candles, blow bubbles, suck from a straw, blow his nose?
From a nutritional standpoint, some of these kids benefit from increasing the protein in their diet. You can do that with the protein drinks that body builder/work out types get at the drugstore. Protien bars can help too. Most kids with low muscle tone also have low tone in their jaws and just don't eat enough meat - unless you count chicken nuggets as "meat!" And if a child has low tone, they aren't likely to ever eat enough protein in their diet and probably need more than the average person, so you can supplement with a protein powder drink or bars. Protein and all the things it contains are necessary for building muscle, which of course is necessary for having core stability.
From an activity standpoint, you can encourage him to do lots of vestibular activities - movement based play. Riding toys, swings and climbing are all great for developing proximal stability. The more the better!
It might be that some home activities could increase his foundation of proximal or core stability, thereby improving his hand function. Sort of like building a good solid brick fuondation on a house, so that the top floor doesn't collapse.
It doesn't sound at all like dysgraphia to me. But that's just my opinion via message forum! Having not ever met or evaluated your son, please be advised that my suggestions here do not take the place of any advice or recommendations you have received from health care professionals! Just my thoughts based on what I'm reading here.
