非住宅物業租客拖欠租金及收回物業

See here:

http://www.judiciary.gov.hk/tc/crt_services/pphlt/html/lands.htm

It pretty much explains everything you need.

By the way, you need a lawyer.

Unfortunately, only your father can sue the tenant(s), you can help your father pretty much everything except appearing in the court.

It does not matter if you have power of attorney. (The only exception is your father has been declared mentally incompetent and you are the appointed legal guardian.)

2014-09-05 18:36:36 補充：
1. No. That's why I said you need a lawyer, which I have just explained as above.

2. Everything - you will have a better idea on how the system works.

可向之發律師信,限期清理租金,過期後便將之告上法庭,最後,可通過執達吏收樓,但過程繁複,拖的日子很久,最近,香港有"業主聯會"這類組織,,由業主組織統一辦理對"租霸'的事宜.可能會有切實的意見或幫助,可在網上查出其電話,並與之聯絡.