For the following sentences:
- Alex has been my friend for a long time.
- Alex has been a long time friend of mine.
Do both of these sentences imply that "Alex" is still my friend?
The first sentence is fine, but the second sentence is not very idiomatic. The verb "has been" is usually followed by an expression describing a time interval, unless the interval is already understood by both parties to the conversation. The phrase "a long-time friend of mine" does not directly express a time interval, even though it implies one. I would rephrase the second sentence as