What to tell someone when they ask " How is mum going". Please I would love to hear your suggestions.

So I get asked "How is mum going" from people that know her but not all know about what Huntington's Disease is. I don't know what to say. I usually say good or good day or bad day but it never seems enough no matter what I say.
So here is the question should I tell them everything I know? or come up with one standard answer? or tell them little?

If you have a suggestion let me know.
or have been in the same drama let me know what you did.

I would be great to hear you answers.