One spouse retired in 2023, other spouse still sole proprietor

Joint should still be better.  Do you get Social Security?  You get a higher standard deduction even if 1 spouse has no income.   Some reasons for Joint.  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.

Also if you file Married Filing Separately up to 85`% of your Social Security becomes taxable right away even with zero other income.

For your personal return, you can file MFJ. The IRS has a quick quiz to help determine the Filing status that is best for you.

For the business:

• If you live in a community property state, you have been filing sch C for each of you. You retire and she claims it all. 
• If you don't live in a community property state, you have been filing partnership returns. The partnership needs to be dissolved.

We each had separate businesses. No partnership. Both sole proprietorships.

So, just file MFJ for personal and for business enter he income and expenses?

Yes.  Don't change a thing except removing the one business that is closed.  Filing jointly will be best for both of you.

@mhr1