Hi I'm a Filipino and my boyfriend is Iranian living in the Philippines.

Aimee, he can probably get HK visa.
If he goes there for sightseeing purpose, the required documents include copy of his passport, the application form, a passport-style photo, proof of his financial support, proof of transportation and accommodation arrangement, and his travel itinerary as well as his residence permit in Philippines. And then submit his application to the embassy of PRC to apply for it.
If the embassy deals with the application on its own, it usually takes 4 working days and costs 1,600 pesos; if the application is transferred to HK immigration department, 4 – 6 weeks are needed and it costs 2950 pesos.