Learn English – “Partial Deaf” or “Half Deaf”

I'm stuck with a situation.

Scene 1:

Mike met with a serious accident and he lost his sense for his left ear. As a result, he can listen through only right ear, the left ear is not working.

Scene 2:

Gary cannot listen to you unless you speak loudly. Say, if you and I can hear the sound of 'x' decibels, he requires 'x+5' decibels.

In my medical practice, we call 'partial paralysis' if the condition has not involved the organ fully. Said that, if you are partially paralyzed, you can still move the affected hand but not fully as there's no strength or power.

The question:

What do we call Mike? Half deaf? And what about Gary? Partial deaf?

Is there any idiom, word for these men? I'm not looking for any medical jargon.