Jehoiachin is not allowed to return to Jerusalem (for reasons unknown to us), but his life becomes much more pleasant. Till he dies, he enjoys a rich and comfortable life.
We should see the ending of 2 Kings against the background of Solomon’s prayer at the inauguration of the temple (1 Kings 8:46–50). What Solomon presents to the Lord there, you see happening: the mercy arises for those who have captured and exiled them. Though we do not read that Jehoiachin has prayed in such a manner, it is a possibility. And even if it were not so, we still learn from this conclusion of 2 Kings that the Lord does not leave his people. Despite the exile, 2 Kings ends with hope. And yet, this hope is of a lower order than the closure of 2 Chronicles.
30 and for his allowance, a regular allowance was given him by the king, according to his daily needs, as long as he lived.