This is another in the family of How are you, How do you do, and so onHow are you keeping?
Is the above equivalent to "How do you do?"
I think it is an enquiry about health of the other who has the history of bad health?
Ditto in rural Canada, but I haven't heard it since the seventies, and then only in my grandparents' generation.In some rustic American English, this is an exact equivalent to "How are you?"
There is no suggestion of prior health problems.
I think this may be derived from Scottish English, but that is outside my range of knowledge, so wait for someone from Scotland to confirm or deny.