J.S.
With the toileting issues added in to yesterday's post, with the kidney and UTI issues likely from withholding urine and feces, his lack of "getting it" on why manners are important, his disinterest in social activities... everything you added here today including yesterday really does paint an Autism picture to me.
And if it's indeed Autism (which Asperger's is, make no mistake) then he will not outgrow it. He will need some specialized, tailored therapies to help him.
You can try minimizing some behaviors by reducing or eliminating some things from his diet such as high fructose corn syrup, artificial food dyes, and see if he's lactose intolerant, gluten intolerant, or has any other food allergies. When a child with Autism doesn't feel well due to food allergies and intolerances their autistic behaviors are worse than they normally would be. Not to mention the chemical components of things like HFCS and food dyes are like giving 40 proof alcohol to a child because their liver and kidneys can't metabolize it, so it courses through their bodies including the brain until they can expel it.
Reducing video games and TV is a must. Those things can be very engaging and educational for an autistic child, but they draw the child away from social interactions. I should say that we caught my daughter's ASD somewhat early... she was in preschool... and she's 9 yrs old now and we still have to really work with her on manners. Hello, good-bye, please, thank you... she's good at it sometimes but most times she needs reminders. It's when eye contact is required that she fudges it. Social awareness and the social niceties and rules that seem obvious to us, even the unwritten ones, are often seemingly impossible even for adult autistics who have had a lot of training and practice.
You might try establishing as much of a stable routine as you can and post it in a couple of easy to see locations in the house. The fridge, the front foyer, his bedroom, the bathroom. Include every major aspect of his day with the time on it. Laminate it. Use velcro for days when you have to add in a variable. He'll probably do well if he doesn't have to deal with surprises as much.
I would also suggest getting the books "Raising a Sensory Smart Child" and "The Out Of Sync Child." They are about Sensory Integration Disorder, but address it very strongly regarding having it with Autism. I also suggest "Different, Not Less" and "The Way I See It" by Temple Grandin. They're all very good reads and you may recognize your stepson in them. There's no shame in ASD... and perhaps with these books you can help your husband see that. There's no shame in asking for help when the family isn't qualified therapists and specialists.