Yes you both have to file the same way. Even if he has less than the Standard Deduction. Even if it’s zero. What state are you in?
If one person itemizes deductions on Schedule A then the other one must itemize too, even if it's less than the standard deduction, even if it is ZERO! And if you are in a Community Property state it can be complicated to figure out.
And there are several credits you can't take when filing separately, like the
EITC Earned Income Tax Credit
Child Care Credit
Educational Deductions and Credits
And contributions to IRA and ROTH IRA are limited when you file MFS.
