what do you mean he files separately under a business account? Unless his business is a C-corporation, his income goes on the joint return. Either a schedule C or through a k-1 issued by his business. On a joint return both spouse report all their income and deductions. The other option is for both to file married separate where each would only report their own income and deductions. Generally, MFS produces higher taxes.
if the above differs from what was actually filed run to a tax pro because then there would likely be a misreporting of taxes
