Honestly, the only things I see that will help improve scores are, let him only carry a balance on one card-his card. Currently running 2 for 2 on revolving. 2) Let the accounts age to a minimum 12 mos on the youngest, that can boost anywhere from 20-30 pts depending upon bureau. Lastly, the biggest boost will come from the collections being deleted or aging off (which appears that might be a few years).
The AU account is the same age as youngest, any reason to pick a card that is as young and carries a balance? AU should always be a very much older card with pristine payment history and carry no balance at statement cut.
If he is denied when he applies for a new credit card have him obtain a secured credit card--as long as that creditor reports to all 3 bureaus it will work well for him. he can use any funds on that pre-paid credit card to pay any collections that may be necessary, but having 2-3 accounts open and active in his name is the ideal manner to increase his scores.
Re: Removal of disputes on accounts---You may want to review the manner in which you've requested to have your disputes removed from these accounts. Do you have copies of the letters you have mailed to the creditors or credit reporting agencies requesting your desire to remove the disputes on the file along with the receipt from the Certified Letter when you sent it to them? This is your proof and if 45 days have passed and they no longer comply you can report them to your State's Attorney General. IF that doesn't get results then you've done something outside of the correct process outlined in the Fair Credit Reporting Act and I'd recommend doing your homework again.