His weird interests change so rapidly that it's hard to tell what he likes at any time.
What I mean is:
His weird interests change so rapidly that it's hard to tell what his current ones (interests) are.
But any time is more commonly used in cases like:
- You can call me any time.
- I can handle him anytime.
in the sense of "always" or "without exception or doubt". So—
Does 'at any time' fit in this context? And is 'at any time' grammatical here? Is it idiomatic enough? If not, how would native speakers say this instead?