Is your business an LLC or other personal company where everything is tied to your personal Social Security number? And if so, is that why you can't transfer ALL of the accounts to him? (Just trying to figure out what exactly the issue is that you'd need the CC# again?)
And if you are an LLC, have you talked to a Tax Accountant?? If not, do not transfer anything until you do!!! Switching the existing bank account names from yours to his may be immediate INCOME. Even though you say it's the Company's money, the IRS may look at it as money going from your personal account (remember LLC is tied to your SS#) to him.
I'm not an Accountant. Just want you to double check.