A seasoned citizen client comes in and says he got married last year but wants to file separately.  I informed him that it would cause him to pay more because it would make his social security taxable.  His new spouse has already filed her return herself.  She incorrectly filed single.  She did not include her social security in her taxable income.  Jointly they will be better off.  So, do I amend her original return and change it to a married filing joint return and add all of his taxable income, deductions, etc. to her amended return?

I am a Pro Basic User who does this for benefit of friends and family. Any assistance is greatly appreciated.