- Only negative forms of can help have this meaning of cannot avoid.
- Example. No-one can help laughing when he comes on stage.
- can help can have the meaning of able to avoid only when the context has already established the use of can't help.
- Example. A: I can't help being scared. B: Of course you can help it.
- This is a catenative verb that takes the gerund (-ing) or, with but, the bare infinitive.
- Alternative structure with but followed by the bare infinitive. I can't help but agree with you.