There are over 400 types of anemia, so there are many possibilities. But not very many forms are inherited.
Good luck, Phate. I have an idea as to what your dad has, but I'm keeping quiet. Are you sure your dad has a genetic marker for his anemia?
We're not sure yet. One doctor said it might be from an infection, another said it might be hereditary. We'll know for certain once my parents come back from the specialist.