Father's mate to obtain treatment in Canada (8)
I believe the answer is:
manitoba
'in canada' is the definition.
('Manitoba' is part of 'canada')
'father's mate to obtain treatment' is the wordplay.
'father's mate' becomes 'ma' (I am not sure about this - if you are sure you should believe this answer much more).
'treatment' indicates anagramming the letters.
'obtain' with letters rearranged gives 'nitoba'.
'ma'+'nitoba'='MANITOBA'
Can you help me to learn more?
(Other definitions for manitoba that I've seen before include "Strange boatman I find in Canada" , "Winnipeg area" , "northern territory" , "Canadian prairie province" , "Canadian lake" .)