I'd advise that he get hold of all three of his credit reports, and dispute all of the debts. If they are that old, they're probably outside of the statute of limitations so it's NOT recommended to pay them. Also, the creditors probably won't have the information to prove that he owes, therefore they have to delete from the credit reports.
Is the apartment being reported to credit? Usually that doesn't happen unless it's gone to a collection agency. I would advise looking at that one very carefully. How exactly did the landlord arrive at the amount? Sometimes they will try to cheat you. If you break the lease and the apartment gets re-rented right away, you can't be charged the entire amount of the lease.... it's limited to what the landlord lost. Also, sometimes they'll try to bill for things which are normal wear and tear. For instance, they tried to bill my wife to change the carpet, when it had never been redone in 10 years (normal wear and tear dictates that it should be changed every 2 or 3 years.) If they're attacking his credit for debts like this, THEY may be liable.
There used to be "no doc" loans, but probably not anymore. Best bet is probably to attack his credit reports.