The bold in the first question is wrong/not used often in English. The correct answer would be, it needs to be sharpened.
The second question is correct, but a bad sentence. This sentence can be interpreted two different ways.
The first being that John is so close to you that you feel as though he is your cousin, when technically not. Note: Usually Americans use people from their immediate family. Aka brother, sister, mother or father...
The second is that John is literally a cousin of yours. The "to me" basically means exactly what it is.
Student or Learner