Spouse filed (MFS) taking standard deduction and I need to file taking itemized deductions. Should he do an amended tax form switching to itemized before I file?

Yes, he should.

You must both either take the standard deduction or itemize, so if you file on a different method, the IRS will send a letter with penalties to the spouse who took the standard deduction disallowing it- it is best to amend first to prevent this.

Here is some information you may find helpful: Is it better for a married couple to file jointly or separately?