Locals here say drunk has become quite rigid and set in his ways (8)
I believe the answer is:
ossified
'set in his ways' is the definition.
'ossified' can be an answer for 'set' (thesaurus). I am unsure of the 'in his ways' bit.
I can't explain the rest of the clue.
Can you help me to learn more?
(Other definitions for ossified that I've seen before include "Changed into bone, or rigid and unprogressive" , "Made hard like bone - or commonly drunk" , "rigidly conventional" , "If so, dies being turned into bone" , "Changed into bone or slangily drunk" .)