any longer

[color=indigo]1-I don’t think he will help me any longer.

Can’t this sentence have two meanings:
[color=blue]a-I think he will stop helping me
[color=red]b-I no longer think he will help me. I used to think that he would help me, but I don’t think that any more.

Gratefully,
Navi.

To me, I don’t think meaning b would apply here. If that is what you meant, you would have to say, “I no longer think he will help me.”

Thank you very much Luschen,

What do you think of this one:

[color=indigo]2-I found out that he had left the country on Monday.

Could that be used instead of:
[color=blue]2a-I found out on Monday that he had left the country.

Or would it always mean:
[color=red]
2b-I found out that on Monday he had left the country.

Gratefully,
Navi.

No, that one is more ambiguous. To me it could definitely either mean 2a or 2b. To be more clear you would have to use one of the options you give.