1) It's a false statement.
Let suppose we have one NFA for some regular language and it's M. so what does it mean by complement of this NFA it's basically M' now you're asking
whether for NFA L(M')=(L(M))'?
this statement is true for DFA , but not for NFA , reason is simple , for DFA , every final state is accepting state and every Non-final state is rejecting state , same is not true for NFA , because it may happen that for some i/p we 're reaching some final state and non-final state as well.
How does we define L(NFA)? it's like for some input string W , after complete scanning of W , if at least one final state is reached , then this W is part of language.Let suppose after consuming i/p W , we reach 3 states q1,q2,q3 so if out of those 3 states , if at least one is final state then it's acceptable input. But for DFA , it can't happen for a particular i/p only one final state is possible.
L(M') is achieved by just convert final state to non-final state and vice versa.
so you can see for i/p W , q1,q2 was non-final states and q3 was final state and it was acceptable i/p in original NFA but in complement of NFA , q1,q2 are final state and q3 is non-final state , but as w is still reaching atleast one final state , it's still valid i/p , does it happen in complement of language? No.
Complement of language is defined by (L(M))'= ∑*-L(M) , it's not that easy to evaluate but we just know that complement of a language is everything that is not part of language.
2)here we have only one final state , make this non-final state , what we got? Nothing but ∅.