Jenny, have you heard about Mike?
-No, I haven't. What about him?
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What is the meaning of 'What about him?'
What other expressions can we use instead of that?
"What about him?" = What [have you heard ... or ... do you know] about him?
You can also say or ask any of these:
No, I haven't. Tell me what's up.
No, I haven't. Tell me what's going on.
No, I haven't. Tell me what the problem is.
No, I haven't. Let me know what's up.
No, I haven't. What's happened?