I repotted my Chinese dwarf rhododendron yesterday, and I plucked its dead leafes today.
But my older brother says that she is dead!!
I think that she is still alive!
Please can you tell me if she is still alive?

It looks a bit dead to me, it should have shoots growing well now. Where have you kept it? If it was outside where it should be then maybe it became very dry sometime. If it was inside then it was inevitable that you would kill it.
If it was out and did get dry then keep it watered and in the shade, prune it back and hope.
What were the roots like? If they were black and soft then they were probably dead and should have been cut off, if they were white and quite hard then they were probably still alive.
IT has two chances,
Geoff.