Please note I'm not a teacher.
Helpful means willing to help or useful so you can use helpful with things or ideas.
That sentence needs a wider context, I think.(2) Your words are helpful.
If friend of mine gave me a list of words to learn before I went to deal with a problem or before exam I'd say that; or Your words were helpful / useful;
I'd say "what you said was helpful" if I refer to what he said.
Your words are comforting - if sb says something that makes me feel better.
You may google for collocation; Set language to english and put :
"* is helpful"