Could you tell me if this usage is correct or not about "get through" as the meaning of "get well" ?
I don't think you can replace "get well" with "get through," but we say we survive / get through an illness, or a crisis, which is a little different from surviving an accident, in that there's an extended period of danger where your prospects might be in question; that is, you might not "get through."

So, continuing to play around with this, it might work as a replacement in the negative:

How is your brother coming along in his fight against pneumonia?

It looks as though he might not get through. (might not survive; might not get well.) I can't quite picture it in the afirmative. Maybe BrE.

"Pull through" is much more common in my experience. "I think he's going to pull through." I don't think he'll pull through."
Dear Avangi,

I appreciate for your kind reply. I can understand it clearly. Thank you very much.Emotion: smile