it may not be a valid question but I wanna know that 'is the above mentioned sentence correct or incorrect'? Because as I was discussing this sentence with one of my friends, he told me that you haven't used 'neither...nor' in a correct way! I got astonished at that time but then he told me that 'Neither can he eat nor sleep' is grammatically correct. But now I want your views about my friend's sentence and mine.
Your idiomatic choices are:
He can't either eat or sleep.
He can neither eat nor sleep.
Neither can he eat nor sleep. note the inversion
The last is something of an archaism, and would be considered formal or literary and is rarely used.