No one should be using their SSN, that is just plain STUPID. A PTIN is required: Anyone who prepares or assists in preparing federal tax returns for compensation must have a valid 2023 PTIN before preparing returns. All enrolled agents must also have a valid PTIN. https://www.irs.gov/tax-professionals/ptin-requirements-for-tax-return-preparers

You certainly could step in and just become the preparer. I hope you are happy with the choice you made to assume total responsibility for everything this other person has done so far. 

How in the world did you engage a preparer that did not yet have a PTIN? 

Get an EIN pretty much immediately, if you qualify:

https://www.irs.gov/businesses/small-businesses-self-employed/apply-for-an-employer-identification-n...

And stop giving out your SSN.

If you want to efile:

https://proconnect.intuit.com/support/en-us/help-article/electronic-filing-identification-number/obt...

https://proconnect.intuit.com/support/en-us/help-article/business-address/register-efin-intuit-e-fil...

https://proconnect.intuit.com/support/en-us/help-article/electronic-filing/e-file-tax-return-proseri...