If he/she is in HR & admin what is the real percentage he is in HR? and what is the activities he is taking care of in HR? depending on the answer to this question I can tell you how far he can succed in HR field...

From my point of view HR can be best said as maintaining the human asset in the office, sustaining them, retaining them for long term growth of the comapny. ]
How to retain them?

By developing good organisational policies, satisfying them in all aspects.

In short it can also be defined as, providing good resource to the company.