X
A good health is much more important than money.
VGood health is much more important than money.
X
She attributed his bad temper to an ill health.
VShe attributed his bad temper to ill health.
Health
is a non-count noun. "Good eating habits are conducive to good health."
grateful
X
I am very thankful for all your help.
VI am very grateful for all your help.
Grateful
is the normal word used to talk about people's reactions to kindness,
favors etc. "She wasn't a bit grateful to me for repairing her car".
Thankful
is used to talk about people's feeling of relief at having avoided a
danger of some kind, or at having come through an unpleasant experience. "We
should all be thankful that nobody was hurt."