In regards to SEC clearances, POTUS can revoke it using EO-12968 and EO-10865.

Taking that into consideration, Trump could very easily revoke HRC clearance, as she meets almost every single criteria mentioned here:

https://news.clearancejobs.com/2014/08/23/guidelines-revoking-security-clearance/

They must want her to access all of the information Team Trump has on her. Once she aquires it, Trump can revoke her clearance and then use all of the information she stole against her as that evidence can now be used in court.