Only residents with HKPR can sponsor resident visas for their parents. You might be able, as a non-PR, to help him get a visit visa, and help him extend it at HK ImmD, but that is not publicly codified. ImmD decides on a case by case.
Having him settle down in Shenzhen until you get PR, and possibly live with him (I used to live in SZ while working in HK) either full-time or on and off could be the best solution.