Why was 'your dad is in a good state' rejected? The suggestion was 'shape' for 'stan' which would be more general, whereas 'state' is a passing condition. Which is it?
Is there something wrong with using definite article "the" in this case?
Indefinite article, or no article at all, would both be fine. Definite article would be unnatural English.
"Your dad's in a good condition" triggered a spurious Missing Space Error ;)