Dana,
This might be worth checking out:
EUROMEDICA BLUE CROSS
Vizyi - Vyzantos 1
Thessaloniki, GR 54636
Tel: 2310-966000, 2310-966100
Fax: 2310-966200
www.kianous-stavros.gr/el/epikoinwnia/
While my browser can translate their web pages, I can't translate the pdf file they have on the urology department but it seems they have specific expertise in treating bladder cancer.
Here is a link to their urology information.
www.kianous-stavros.gr/pdf/ourologiko-tmhma.pdf
.
I'd suggest also asking his current urologist, where is the best place for bladder cancer treatment in Greece or the neighboring countries. Call the hospital, get the urology department and see if you can get biographies of the bladder cancer specialists. You can usually tell based on the number of papers they've written on bladder cancer specifically, the number of surgeries they do for bladder cancer, etc.
It appears from other searching that I've done that Greece is a country with a pretty high incidence of bladder cancer (most attribute that to the high incidence of smoking in Greece) so it seems you should have some pretty good docs there with a specialization.
Hope this helps some.
Mike