In OUTCAS it's see and avoid.
The helo pilot has only this option, ie: to use his visual senses. In addition looking for another aircaft in your proximity is hard enough when you are conducting close in collaborative filming with ground units...never mind trying to watch for a speck on the windscreen called a drone.
The drone operator however (who must retain line of site And remain outwith 150m of vehicles, vessels, persons, structures unless exempted also - has two senses working for him: visual and sound. He may not be able to see the chopper but he can hear the damn thing!
QED the onus is almost entirely that of the drone operator to avoid the other aerial platform.