Answer and Explanation:
1. The rhetorical question at the beginning of the poem asks a forgotten old man must never be brought to mind again. This question does not require an answer, but its obvious purpose is to provoke a reflection in the reader about what forgetfulness is and if forgotten people should never be remembered again, especially when that person is an old friend.
2. At the end of the poem the speaker implies that an old friend must not be erased from anyone's mind. This friend also promoted good memories that should never be forgotten, but should be relived.