Of course he already has the license, but further:
(i) Revocation.--A license to carry firearms may be revoked by the issuing authority for good cause. A license to carry firearms shall be revoked by the issuing authority for any reason stated in subsection (e)(1) which occurs during the term of the permit....
I have not found any indication that you are required to notify the sheriff of your change of residence. If you do notify, then he may have good cause to revoke. That's how I read it in my non-lawyer simple English.