Japanese Hospitals?

Hi,
I have a healthcare realated question. My sister will be staying with us for 4 month and she needs to have blood tests done every 2 weeks, in case they go up she'll have to start chemo again. Me and my husband live on a military base and my sister will not have access to the military hospital so we will have to find a doctor or hospital outside the post. I know we will have to pay for the tests and possible chemo, but I am trying to see if others have experience with this. Can we just choose any hospital or doctors office that is english speaking and make appointments? What hopsitals or clincis are more expensive then others? Any info would be greatly appreceated.

yokohama shinmin byouin has a translator service whereby they have volunteer translators available for various languages to accompany patients in discussions with doctors etc for free. You have to book in advance of course when you make an appointment.
not sure about costs for chemo though, I guess without insurance cover it is quite expensive.
Do they have insurance that covers hospital treatment in japan?
Also, Im not sure but, if they are not living in japan (i.e. not paying citizen/resident tax) maybe these translation services are not available, worth checking though.