The assumption is not necessarily correct. While the seven years affects the credit report, the statute of limitations for collections may be different and is based on the State law where the debt was given (or a Federal law for NA banks).
Keep in mind that the creditor can reset the clock any time by taking legal action, for example filing a law suitelawsuit in a court to garnish some of his income or put a lien on some of his assets. Many times, just contacting the debtor is enough to reset the clock. The statute of limitations on collections is a legal issue and he should talk to a lawyer about it. Different accounts may have different statutes affecting them.