Welcome to the forum Leonard although I'm sorry for the reason you are posting. 

As we are a UK Charity we aren't able to help you specifically however we do have some general information on our website about cancer treatment for overseas patients which may be useful, especially as it has a section where you can find cancer organisations in Greece that may be able to help with this. To find out more, just click here.

I hope this helps and that you are able to get the funding needed for your fiancee's mum to have her treatment.

Kind regards, 

Steph, Cancer Chat Moderator