You mentioned that he is emotionally between 2 and 4. For a 2-4 year old to want to play most of the day with a pair of shoes or whatever isn't all that abnormal. Yes, I know he's 13 and he should be doing more and other things. But if inside he is functioning at the 2-4 year old level, go there for awhile and see if he can progress to the 3-5 year old level.
What would you be doing with a 2-4 year old with regard to life skills? Picking out their own clothes and putting them on. Safety skills, manners, social interaction, etc. Work at the approximate level that he's been tested out to and see what happens. Sure he should be doing other things, but if he's only been with you 4 years and has progressed as far as you've mentioned that's pretty good considering he was SO behind at age 9.
With "normal" child development there are slower and faster cycles that they go through. Perhaps he needs some reinforcement and the encouragement of going over what he already knows. Firming up areas he's shaky in and doing the things that he's mastered so he gets LOTS of accomplishments done each day -- just a few skill levels back.
This may be what you have already done, it may be totally out of line, etc. but I thought that maybe if mentally stepping back and going back a few developmental stages for awhile gives you some renewal for going on for the long haul, then it isn't a bad thing to try. I don't know you, or your son, or your family dynamics, so take what you can use and toss the rest.
